JDS Feb 23-March 21 GC

Question 1

Talmón et al., 2023Effect of animal activity and air temperature on heat production, heart rate, and oxygen pulse in lactating Holstein cows

Answer 1

We concluded that O2P in dairy cows was slightly affected by both animal posture and activity, but remained unaffected by air temperature within 8 to 32°C.

Question 2

Molinari et al., 2023 Prepartum heat stress in dairy cows increases postpartum inflammatory responses in blood of lactating dairy cows

Answer 2

Our results imply that prepartum Heat Stress during late pregnancy has carry-over effects on postpartum innate immunity, which may contribute to the increased incidence of uterine disease observed in cows exposed to prepartum HS.

Question 3

Evaluation of feed restriction and abomasal infusion of resistant starch as models to induce intestinal barrier dysfunction in healthy lactating cows
Piantoni et al., 2023

Answer 3

The lack of consistent responses in inflammatory biomarkers suggests that Feed Restriction and “Restricted Starch” did not meaningfully affect intestinal barrier function

Question 4

Effects of hindgut acidosis on metabolism, inflammation, and production in dairy cows consuming a standard lactation diet
Abeyta et al., 2023

Answer 4

Despite minor changes in postabsorptive energetics and leukocyte dynamics, abomasal starch infusions and the subsequent hindgut acidosis had little or no meaningful effects on biomarkers of immune activation or production variables.

Question 5

Antimicrobial activities of polyhexamethylene biguanide against biofilm-producing Prototheca bovis
causing bovine mastitis
Fidelis et al., 2023

Answer 5

These findings suggest that polyhexamethylene biguanide (PHMB) has the potential to be used for teat and milking-equipment disinfection for the prevention of mastitis-causing Prototheca spp. in dairy herds.

Question 6

Evaluation of reticuloruminal temperature for the prediction of clinical mastitis in dairy cows
challenged with Streptococcus uberis
Rodriguez et al., 2023

Answer 6

• Intramammary challenge with Strep. uberis increased RRT by 0.54°C [95% confidence interval (CI): 0.41, 0.66] at 24 h after the challenge, which remained elevated until the end of the study
  -The accuracy of CM for a given severity score was 90.9% (95% CI: 70.8, 98.9) for mild cases, 85.2% (95% CI: 72.9, 93.4) for moderate cases, and 92.9% (95% CI: 66.1, 99.8) for severe cases
• Overall, the results of this study indicated that RRT was affected by the intramammary challenge with Strep. uberis and the RRT-generated alerts had similar accuracy as reported for other sensors and algorithms

Question 7

Management practices associated with Johne’s bulk tank milk ELISA positivity

Imada et al., 2023

Answer 7

The cleanliness scores of older heifers and their exposure to mature cow manure was significantly associated with JD control; farms with highly contaminated weaned and bred heifers and those that had exposure to mature cow manure were more likely to be unsuccessful in their JD control efforts

Question 8

Methods used by Canadian dairy farmers for on-farm euthanasia and the emotions associated with the decision and the practice of euthanasia
Denis-Robichaud et al., 2023

Answer 8

Unacceptable euthanasia methods, such as standard 0.22-caliber long rifle for adult cows or no adjunct method following the use of captive bolt, were used by 25%, 18%, and 58% of the participants for calves, replacement animals, and dairy cows, respectively.

Question 9

Selective treatment of nonsevere clinical mastitis does not adversely affect cure, somatic cell count,
milk yield, recurrence, or culling: Meta-analysis
De Jong et al., 2023

Answer 9

We did not identify any differences between selective and blanket treated CM cases for the outcome measures clinical cure, proportion new IMI, SCC, milk yield, recurrence,
and culling, although noninferiority margins could not be determined.

Question 10

Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part III—Associations of management and dietary factors with analytes, health, milk yield, and reproduction
Kerwin et al., 2023

Answer 10

• Our results support increasing the proportion of particles on the 19-mm sieve of the Penn State Particle Separator, optimizing bunk space, and not overfeeding metabolizable energy (ME), to decrease the prevalence of elevated postpartum NEFA, BHB.
• not vaccinating in the calving pen, minimizing the number of prepartum and postpartum pen moves, and avoiding long stays in the calving pen after parturition

Question 11

Pegbovigrastim treatment resulted in an economic benefit in a large randomized clinical trial
in grazing dairy cows
Barca et al., 2023

Answer 11

• Overall, PEG treatment increased the partial net return, resulting in an economic benefit per cow per year of $210 ± 100.
• The cost of treatment of clinical mastitis was lower for PEG treated cows compared with control cows ($9 ± 3). The largest nonsignificant difference was seen for the cost of culling; additionally, PEG treatment numerically reduced the cost of culling by $145 ± 77.

Question 12

Modeling the economic impacts of mobility scores in dairy cows under Irish spring pasture-based management

O´Connor et al., 2023

Answer 12

• The analysis showed that a 17% decrease in farm net profit was achieved in the worst outcome (wherein just 5% of the herd had optimal mobility) compared with the perfect herd.
• This was due to reduced milk yield, increased culling, and increased treatment costs for mobility issues compared the ideal scenario

Question 13

Feeding behaviors collected from automated milk feeders were associated with disease in grouphoused
dairy calves in the Upper Midwest United States
Perttu et al., 2023

Answer 13

• Total milk intake (mL/d), drinking speed (mL/min), interval between visits (min) to the AMF, calf age (d), and rewarded visits were significantly associated with dairy calf health status.
• These results indicate that as total milk intake and drinking speed increased, the risk of calves being sick decreased. In contrast, as the interval between visits and age increased, the risk of calves being sick also increased.

Question 14

Farm-level risk factors for digital dermatitis in dairy cows in mountainous regions
Weber et al., 2023

Answer 14

• Results of model 1 (i.e., aspects related to BDD introduction) revealed that access to mountain pastures during the summer season (odds ratio, 95% confidence interval: 0.12, 0.04–0.35), participation in dairy shows (0.32, 0.11–0.94), and the number of new animals introduced into the farm during the last 2 yr (1.28, 1.12–1.52) were significantly associated with the occurrence of BDD.
• Model 2 (i.e., aspects related to BDD establishment) showed that cows kept in freestalls were at higher risk for BDD compared with those kept in tiestalls (20.65, 1.59–649.37). Furthermore, number of days between diagnosis and treatment of a BDD lesion (10.31, 3.55–81.21) and the amount of concentrate feeding (median 5 kg) per cow and day (7.72, 2.46–6.47) were positively associated with BDD occurrence.

Question 15

Comparison of 2 types of milk flow meters for detecting bimodality in dairy cows
Wieland & Sitka, 2023

Answer 15

• Using BIMLC as the gold standard, diagnostic test statistics for bimodality detected by the on-farm milk flow meter indicated
  o Sensitivity [0.73 (0.54–0.86)]
  o Positive predictive value [0.83 (0.63–0.93)],
  o Specificity [0.94 (0.85–0.98)],
  o Negative predictive value [0.90 (0.81–0.95)].

Question 16

Methods for detecting heat stress in hutch-housed dairy calves in a continental climate
Dado-Senn et al., 2023

Answer 16

The threshold at which respiratory rate and Rectal Temperature began to rise was at a THI of 69 for both or at a Dry bulb temperature(Tdb) of 21.0 or 21.5°C, respectively

Question 17

Production, physiological response, and calcium and magnesium balance of lactating Holstein cows fed different sources of supplemental magnesium with or without ruminal buffer
Lobo et al., 2023

Answer 17

• No effects on body weight and milk yield were observed.
• Treatment with CaMg(OH)2 increased blood concentration of HCO3−, total CO2, and base excess compared with cows fed MgO

Question 18

Effect of prepartum source and amount of vitamin D supplementation on lactation performance of dairy cows
Poindexter et al., 2023

Answer 18

Feeding calcidiol (CAL) compared with Vitamin D3 cholecalciferol (DCHOL) increased yields of colostrum and colostrum fat, protein, and total solids, resulting in an increased amount of net energy for lactation secreted as colostrum (CHOL = 7.0 vs. CAL = 9.0 ± 0.7 Mcal).

Question 19

A meta-analysis of effects of 3-nitrooxypropanol on methane production, yield, and intensity in dairy cattle
Kebreab et al., 2023

Answer 19

The greater the NDF content in the diet, the lower the reduction efficiency for a given 3-NOP dose

Question 20

Invited review: Assessment of reserves in relation to insulin sensitivity and metabolic phenotyping in dairy cows body condition score and body fat
Ghaffari et al., 2023

Answer 20

Overall, reducing the number of cows with nonoptimal body conditions in herds seems to be the most practical solution to improve profitability, and dairy farmers should adjust their management practices accordingly.

Question 21

Intrauterine infusion of a pathogenic bacterial cocktail is associated with the development of clinical metritis in postpartum multiparous Holstein cows
Silva et al., 2023

Answer 21

Unexpectedly, intrauterine infusion of cows with a lower dose of bacteria was more effective than a higher dose, indicating that the bacterial load may affect metritis incidence in a nonlinear manner.

Question 22

Economic losses associated with mastitis due to bovine leukemia virus infection

Nakada et al. 2023

Answer 22

In summary, High pro-viral load (H-PVL) cows were more susceptible to subclinical mastitis than non-infected and low-proviral-load cows, and mastitis due to BLV infection was projected to c ause significant economic losses.

Question 23

Effect of mechanical premilking stimulation on milking duration in late lactation
Upton et al., 2023

Answer 23

Based on the results of the study, we found merit in applying 60 s of mechanical pre-stimulation at a.m. milking from a milking duration perspective. However, the strategy was not as successful for the p.m. milking. Analysis of the milk flowrate profiles recorded during the study suggest potential utility in employing different machine settings for various milkings based on anticipated yield and level of udder fill

Question 24

The effects of dexamethasone administration on physiological, behavioral, and production parameters in dairy cows after a difficult calving
Swartz et al., 2023

Answer 24

The administration of dexamethasone resulted in changes in behavioral measurements, which could suggest a reduction in discomfort; however, due to the reduction in milk yield for the first month follow-ing calving, DEX administration may not be applicable for typical farm use

Question 25

Effects of a single transdermal administration of flunixin meglumine in early postpartum Holstein Friesian dairy cows: Part 2. Milk yield, culling risk, and reproductive performance
Schmitt et al., 2023

Answer 25

We conclude that a single transdermal administration of FM in early postpartum dairy cows on farms at risk for excessive postpartum inflammation slightly increased milk, milk fat, and milk protein yields in PRIM cows and decreased these variables in MULT cows. Neither culling risk nor fertility was affected by treatment in this study.

Question 26

Effects of a single transdermal administration of flunixin meglumine in early postpartum Holstein Friesian dairy cows: Part 1. Inflammatory and metabolic markers, uterine health, and indicators of pain
Schmitt et al., 2023

Answer 26

It can be concluded that FM treatment slightly reduced inflammation and diminished the risk for metritis in primiparous cows, improved metabolic profile in multiparous cows, and reduced expressions of pain in all cows.

Question 27

Changes in biomarkers of metabolic stress during late gestation of dairy cows associated with colostrum volume and immunoglobulin content
Rossi et al., 2023 (Abuelo last author)

Answer 27

• Cows with high IgG showed higher concentrations of glucose compared with low IgG.
• Cows with high IgA had higher concentrations of cholesterol, reactive oxygen and nitrogen species, oxidant status index, and total protein, whereas beta-hydroxybutyrate and glucose were lower compared with low IgA.
• Biomarkers of metabolic stress were not significantly different between high IgM and low IgM.

Question 28

Evaluation of potential biomarkers to determine adequate colostrum provision in male dairy-beef calves upon arrival at the rearing facility beyond 14 days of age
Pisoni et al., 2023

Answer 28

Because of their low cost, quickness, and ease of measurement, GGT and TP were good indicators of colostrum intake in calves arriving at rearing facilities beyond 14 d of age.

Question 29

Effect of dose and frequency of prostaglandin F2 alpha treatments during a 7-day Ovsynch protocol with an intravaginal progesterone releasing device on luteal regression and pregnancy outcomes in lactating Holstein cows
Holper et al., 2023

Answer 29

The addition of a second PGF treatment on d 7 and 8 of a 7-d Ovsynch protocol increased luteal regression and decreased mean P4 at G2. Cows treated with PGF2 alpha 2 times 24 h apart showed greater P/AI, compared with cows treated with an increased dose of PGF2 alpha.

Question 30

Voluntary heat stress abatement system for dairy cows: Does it mitigate the effects of heat stress on physiology and behavior?
Grinter et al., 2023

Answer 30

In conclusion, voluntary soaker use related positively to the THI, but no major productive, physiological, or behavioral differences were observed between soaking treatments

Question 31

The effect of antibiotic versus no treatment at dry-off on udder health and milk yield in subsequent lactation: A retrospective analysis of Austrian health recording data from dairy herds
Sigmund et al., 2023 (Wittek last author)

Answer 31

Dairy cows dried off with antibiotics were found to have an improved Milk yiled ration MYR and cell count ratio CCR compared with the nontreated group, however the data also showed that only a small number of bacteriological examinations
were performed before dry-off and a relatively large proportion of the dairy cows with negative bacteriological cultures or low SCC before dry-off were still dried
off with antibiotics.

Question 32

Feeding encapsulated pepper to dairy cows during the hot season improves performance without affecting core and skin temperature.
Vittorazzi et al., 2022

Answer 32

A feed additive containing encapsulated pepper fed at 0.75 or 1.5 g/d can improve yield of fat-corrected milk and milk solids by increasing feed intake without affecting nutrient digestibility and body temperature of lactating cows during the hot season.

Question 33

Apparent prevalence and risk factors for udder skin diseases and udder edema in Bavarian dairy herds

Groh et al., 2022

Answer 33

Freestall housing and comfort rubber mats were identified as risk factors for udder cleft dermatitis on a herd level

Question 34

Development and validation of a clinical respiratory disease scoring system for guiding treatment decisions in veal calves using a Bayesian framework.

Berman et al. 2022 (Buczinski last author)

Answer 34

 We found that calves with 2 of the following findings cough, unilateral or bilateral ear droop or head tilt, or increased rectal temperature ≥39.7°C were considered positive and had a 31% chance of having active BRD. Without at least 2 of these 2 findings, a calf had a 100% chance of not having active BRD.
 At the batch level, we found that a batch with ≥3 positive calves among 10 calves sampled 2 wk after arrival at the fattening unit had a 94% chance of having an active BRD prevalence ≥10%.
 A batch with <3 positive calves had a 95% chance of not having an active BRD prevalence ≥10%.

Question 35

Deep convolutional neural networks for the detection of diarrhea and respiratory disease in preweaning dairy calves using data from automated milk feeders

Ghaffari et al., 2022

Answer 35

 The number of unrewarded visits to the milk feeder and MR intake were the main factors to predict calf disease in restricted-fed calves. Despite the relatively small sample size, the results provide strong evidence that daily feeding behavior data from AMF can be used to identify calves at risk for disease.

Question 36

Determination of milk concentrations and pharmacokinetics of salicylic acid following acetylsalicylic acid (aspirin) administration in postpartum dairy cows

Fritz et al., 2022

Answer 36

Results from this study suggest that the current milk withhold recommendation for dairy cattle administered Acetyl Salycilic Acid (ASA) may need revision to 120 h (5 d) and that ASA administration may mitigate postpartum inflammation through reduction in prostaglandin production for up to 12 h after treatment

Question 37

Evaluating the effectiveness of colostrum as a therapy for diarrhea in preweaned calves

Carter et al., 2022

Answer 37

Supplementation of 8 feedings over 4 d of 2.5 L of a mixture of milk replacer at 65 g/L and bovine colostrum replacer at 65 g/L compared with 8 feedings over 4 d of 2.5 L of milk replacer at a concentration of 130 g/L was determined to resolve diarrhea sooner and improve growth levels in young dairy calves

Question 38

Effect of Saccharomyces cerevisiae fermentation product on oxidative status, inflammation, and immune response in transition dairy cattle.
Sivinski et al., 2022

Answer 38

 Supplementation with SCFP did not affect overall oxidative, inflammatory, or immune parameters.

Question 39

Research and application of a new multilevel fuzzy comprehensive evaluation method for cold stress in dairy cows

Fu et al., 2022

Answer 39

The results showed that the mean mild cold stress durations were 605.3 h (25.22 d) and 725.5 h (30.23 d) and the moderate cold stress durations were 67.2 h (2.8 d) and 96 h (4.0 d) on the south and north sides of the barns, respectively

Question 40

Association between prepartum nonesterified fatty acid serum concentrations and postpartum diseases in dairy cows

Nicola et al., 2022

Answer 40

The optimal NEFA threshold associated with diseases was ≥290 µmol/L for retained placenta, ≥300 µmol/L for metritis and abomasal displacement, and ≥280 µmol/L for clinical mastitis and hyperketonemia. The level associated with the occurrence of at least one of these diseases in the first 30 DIM was ≥280 µmol/L, but it was ≥260 µmol/L for culling in the first 50 DIM.

Question 41

A randomized controlled trial examining the effects of treatment with propylene glycol and injectable cyanocobalamin on naturally occurring disease, milk production, and reproductive outcomes of dairy cows diagnosed with concurrent hyperketonemia and hypoglycemia

Hubner et al., 2022

Answer 41

 Treatment in hypoglicemia HG cows decreased clinical ketosis, increased milk production in the fifth week of lactation for multiparous cows, and tended to increase 305-d mature-equivalent milk yield (305ME) for primiparous cows compared with untreated cows with the same metabolic profile.
 For cows with hyperketonemiahyperglicemia (HKHG), treatment increased 305ME in multiparous cows and tended to increase 305ME in primiparous cows.
 No differences were found for treatment among any of the metabolic groups regarding reproductive outcomes, nor were any treatment effects found among HK cows. Glycemic status may help identify metabolically challenged early postpartum dairy cows, which may have differential response to PG and B12 treatment

Question 42

Characterization of metabolic profile, health, milk production, and reproductive outcomes of dairy cows diagnosed with concurrent hyperketonemia and hypoglycemia

Hubner et al., 2022

Answer 42

 Multiparous cows with HyperKetonemia HYPOGlicemia (HKHG) had fewer metabolic disturbances (hypomagnesemia, hypocalcemia, elevated NEFA) than HK cows. Cows with HKHG had an increased incidence of clinical ketosis and left displaced abomasum relative to Norm cows.
 Cows with HG had similar metabolic profiles to Norm cows and had lower incidence of retained fetal membranes and puerperal metritis than cows with HK. Multiparous cows with HG produced more milk than Norm cows from wk 10 to 20
 Multiparous cows with HK produced less milk than Norm cows. For primiparous cows, HK did not have a negative effect on milk production compared with Norm cows.

Question 43

Hoof lesions in partly housed pasture-based dairy cows

Browne et al., 2022

Answer 43

 The cow-level prevalence of alarm lesions was 19% during the grazing period and 25% during the housing period; the most prevalent alarm lesion was sole ulcers during both periods.
 We found significantly more foreign bodies within the hoof sole (grazing = 14%, housing = 7%) and overgrown claws (grazing = 71%, housing = 55%) during the grazing period compared with the housing period. Cows with foul of the foot, sole ulcer, white line abscess, toe necrosis or an amputated claw had higher odds of being more severely lame, compared with mildly lame. The strongest correlation between lesions were between toe necrosis and digital dermatitis (r = 0.40), overgrown claws and corkscrew claws (r = 0.33), and interdigital hyperplasia and digital dermatitis (r = 0.31) at herd level.
 At the cow level, the strongest correlation was between overgrown claws and corkscrew claws (r = 0.27), and digital dermatitis and heel erosion (r = 0.22).

Question 44

Is animal welfare better on smaller dairy farms? Evidence from 3,085 dairy farms in Germany

Lindena et al., 2022

Answer 44

• Regression results showed that larger farms tended to achieve a better animal welfare index (AWI) than smaller farms in our data set.
• Although this study focused on the effect of herd size, it is not the only factor affecting animal welfare levels on individual farms. Other variables that we included in the regression to describe the AWI indicate that the knowledge and skills of the farm manager and the amount of time that farms can devote to animals have a positive effect on the AWI.

Question 45

Effects of prepartum supplementation of beta-carotene on colostrum and calves

Prom et al., 2022

Answer 45

Supplementation did not affect colostral or calf IgG concentrations.

Question 46

The first week following insemination is the period of major pregnancy failure in pasture-grazed dairy cows

Berg, et al., 2022

Answer 46

• Fertilization failure (15.8%) and embryonic arrest before the morula stage (10.3%) were the major developmental events contributing to first-week pregnancy failures.
• Embryo elongation failure of 7% contributed to pregnancy failure during the second week.
• The risk factors for pregnancy success that were related to the cows included interval between calving and insemination, and d-7 plasma progesterone concentrations, whereas insemination sire was associated with pregnancy outcome.

Question 47

Associations between ultrasound hepatic measurements, body measures, and milk production traits in Holstein cows.
Piazza et al., 2022

Answer 47

 In conclusion, this study suggests that US measures of liver dimensions of clinically healthy cows are related to their size, whereas pTAG concentrations reflect body condition status, with no particular implications for milk production and productivity

Question 48

Combined biotin, folic acid, and vitamin B12 supplementation given during the transition period to dairy cows: Part II. Effects on energy balance and fatty acid composition of colostrum and milk.
Duplessis et al., 2022

Answer 48

 These results could indicate ruminal perturbation caused by the B8 supplement, which was not protected from rumen degradation.
 Under the conditions of the current study, in contrast to B8+/B9B12- cows, B8-/B9B12+ cows produced more milk without increasing dry matter intake, although these cows had greater body fat mobilization in early lactation as suggested by the FA profile and BW loss.

Question 49

Combined biotin (B8), folic acid (B9), and vitamin B12 supplementation given during the transition period to dairy cows: Part I. Effects on lactation performance, energy and protein metabolism, and hormones.
Duplessis et al., 2022

Answer 49

 In summary, our results showed that, under the current experimental conditions, increasing B8 supply did not improve responses to the B9 and B12 supplementation.

Question 50

Effects of increasing air temperature on skin and respiration heat loss from dairy cows at different relative humidity and air velocity levels
Zhou et al., 2022

Answer 50

• When ambient T was below 20°C the total LHL (skin + respiration) represented approx. 50% of total heat loss, whereas above 28°C the LHL accounted for more than 70% of the total heat loss.
• Both RH and AV had no significant effects on respiration SHL or LHL

Question 51

Effects of wildfire smoke exposure on innate immunity, metabolism, and milk production in lactating dairy cows.
Anderson et al., 2022

Answer 51

 Effects of PM2.5 and THI on metabolism were contingent on day of exposure. On lag d 0, blood urea nitrogen (BUN) was reduced with higher combined THI and PM2.5, but on subsequent lag days, THI and PM2.5 had a positive interaction on BUN.
 Conversely, THI and PM2.5 had a positive interacting effect on nonesterified fatty acids (NEFA) on lag d 0 but subsequently caused a reduction in circulating NEFA concentration.
 Our results suggest that exposure to high wildfire-derived PM2.5, alone or in concert with elevated THI, alters systemic metabolism, milk production, and the innate immune system.

Question 52

Transition milk stimulates intestinal development
of neonatal Holstein calves.
Van Soest et al., 2022

Answer 52

 We conclude that feeding Transition Milk for 4 d following an initial feeding of colostrum stimulates villus, mucosal, and submucosal development in all sections of the small intestine in the first few days of life and improves health and growth.

Question 53

Bayesian estimation of sensitivity and specificity of a milk pregnancy-associated glycoprotein ELISA test for pregnancy diagnosis between 23 and 27 days after insemination in Holstein dairy cows.

Durocher et al. 2023 (Dufur last author)

Answer 53

 Estimated median Se and Sp of the PAG ELISA test conducted between 23 and 27 d after AI were 0.98 (95% credible interval 0.93 to 1.0) and 0.98 (0.89 to 1.0), respectively, when using a standardized corrected optical density threshold of 0.15.

Question 54

Detection of nonpregnant cows and potential embryo losses by color Doppler ultrasound and interferon-stimulated gene expression in grazing dairy cows.
Madoz et al., 2022

Answer 54

 The combination of early Corpus luteum-Blood Perfusion by Doppler US (d 19 to 20) with early embryo detection by B-mode US (d 33–34) could be used to facilitate earlier rebreeding of dairy cows.

Question 55

Environmental factors affecting the conception rates of nulliparous and primiparous dairy cattle.
Ukita et al., 2022

Answer 55

 Both Peak Lactation and Calving to First Insemination strongly affected the conception rate in primiparous cows, which decreased with an increase in PY, even for the group with CFI ≥100 d; however, the conception rate increased for a CFI ≥60 d regardless of PY.

Question 56

Risk factors for delayed milk ejection in Holstein dairy cows milked 3 times per day.
Wieland et al., 2022

Answer 56

 Parity and CDME were associated such that compared with cows in their third or greater lactation, the odds (95% confidence intervals, 95% CI) of CDME were 1.27 (0.71–2.25) for cows in their first and 4.77 (2.47–9.22) for animals in their second lactation.
 The odds of CDME increased with increasing stage of lactation, with an odds ratio of 0.20 (0.11–0.36) for early and 0.28 (0.15–0.52) for mid-lactation animals, respectively, compared with late lactation cows.
 A 1-kg increase in average daily milk production was associated with decreased odds of CDME [odds ratio (95% CI): 0.89 (0.87–0.92)].
 A lameness event during the study period increased the odds of CDME [odds ratio (95% CI): 8.04 (1.20–53.83)], as did a vaccination event 1 wk before the study period [odds ratio (95% CI): 4.07 (0.99–16.71)].

This study confirmed associations between Chronically Delayed Milk Ejection (CDME) and previously reported risk factors and identified several previously less rigorously investigated health and management events that could be associated with CDME. Incremental milk flow rates from individual cows serve as an automated tool to evaluate milk flow dynamics.

Question 57

A calm companion lowers fear in groups of dairy cows.
Stenfelt et al., 2022

Answer 57

Adding a calm, experienced cow to groups of dairy cattle may mitigate fear and thereby improve welfare and safety.

Question 58

Heat stress in a temperate climate leads to adapted sensor-based behavioral patterns of dairy cows.
Hut et al., 2022

Answer 58

 Lying time decreased in the Conventional Milking System group by 36 min/d, in the AMS group by 56 min/d, and in the dry group by 33 min/d.
 Adaptation to daily temperature and THI was already noticeable from a mean temperature of 12°C or a mean THI of 56 or above, when dairy cows started spending less time lying and eating and spent more time standing. Further, rumination time decreased, although only in dry cows and cows on AMS farms.

Question 59

Different reticuloruminal pH metrics of high-yielding dairy cattle during the transition period in relation to metabolic health, activity, and feed intake

Heirbaut et al., 2022

Answer 59

 pH patterns, rather than time pH <6, were associated with metabolic health and feed intake: high variation in daily pH was reflected in higher blood concentrations of nonesterified fatty acids.
 pH deviations of the harmonic model were negatively associated with feed intake and rumination behavior.
 Conclusion: confirms the biological importance of pH metrics focusing on pH variation and pH deviations and provides deeper insight into its associations with metabolic health status, feed intake, and activity during early lactation.

Question 60

Associations between time in the close-up group and milk yield, milk components, reproductive performance, and culling of Holstein dairy cows feeding acidogenic diets: A multisite study.
Venjakob et al., 2022

Answer 60

 In conclusion, a short stay in the close-up group should be avoided to improve milk yield at first test day and to minimize culling risk for parous cows. A long stay in the close-up group (>30 d) was associated with reduced milk production and an increased ratio of fat and protein in milk of parous cows and increased SCS of nulliparous and parous cows.

Question 61

Effects of free-choice pasture access on lameness recovery and behavior of lame dairy cattle

McLellan et al., 2022

Answer 61

 Over the 7-wk period, 42% of cows had at least one sound period (pasture: 55.6%, indoor: 26.9%), but this was more likely for cows with pasture access (odds ratio = 4.1; 95% confidence interval: 1.1-14.6%).
 Pasture cows also spent more total weeks sound compared with indoor cows (2.0 ± 0.34 vs. 0.81 ± 0.35 wk). Cows with pasture access lay down for less overall time than indoor cows (13.9 ± 0.29 vs. 12.7 ± 0.28 h/d) and spent more time standing on pasture (74%) than when indoors (47%).
 These results suggest that lame dairy cows will use pasture when provided with free-choice access, primarily at night, and that access to pasture aids in lameness recovery.

Question 62

The relationships between early lactation energy status indicators and endocrine fertility traits in dairy cows.
Mantysaari et al., 2022

Answer 62

The measured relationships between fertility traits (C-LA and CFH) based on frequent measurements of P4 by Herd Navigator and Energy Status(ES) indicators indicated that increases in ES indicators during the first weeks of lactation can be harmful for the fertility of cow. Therefore, monitoring a cow’s ES after calving is important

Question 63

Graduate Student Literature Review: Role of pain mitigation on the welfare of dairy calves undergoing disbudding

Reedman et al., 2022

Answer 63

As a painful procedure, disbudding has numerous welfare impacts on the calf both during and following the procedure that can be categorized under all 3 principles of animal welfare: natural living, biological functioning, and affective state.
Mechanical nociceptive threshold can be evaluated around the disbudding wounds and is a reliable test in older calves; however, this outcome in very young calves after caustic paste disbudding has been reported to be inconclusive compared with that in older calves. As well, research evaluating xylazine sedation for disbudding has reported both potentially positive and negative results that are difficult to interpret or base suggestions on for the use of this drug

Question 64

Effects of milk replacer allowances and levels of starch in pelleted starter on nutrient digestibility, whole gastrointestinal tract fermentation, and pH around weaning.
Yohe et al., 2022

Answer 64

• Higher SPS calves showed an increase in rumen pH magnitude (1.46 ± 0.07) compared with low SPS calves (1.16 ± 0.07), a decrease in rumen pH in wk 8 (high SPS: 5.37 ± 0.12; low SPS: 5.57 ± 0.12), and a decrease in haptoglobin in wk 8 (high SPS: 0.24 ± 0.06 g/L; low SPS: 0.49 ± 0.06 g/L).
• The majority of differences came from increased starter intake in general, which suggests that with completely pelleted starters the differences in starch and NDF do not elicit drastic changes in fermentation, subsequent end products, and any resulting inflammation in calves around weaning.

Question 65

Effects of replacing inorganic salts of trace minerals with organic trace minerals in pre and postpartum diets on feeding behavior, rumen fermentation, and performance of dairy cows.
Mion et al., 2022

Answer 65

• In conclusion, complete replacement of Salt Trace Minerals by Organic Trace Minerals caused modest changes in rumen fermentation, feeding behavior, energy metabolism, and performance of dairy cows, improving postpartum DMI in multiparous cows and reducing circulating levels of nonesterified fatty acids.

Question 66

Macronutrient profile in milk replacer or a whole milk powder modulates growth performance, feeding behavior, and blood metabolites in ad libitum-fed calves.
Wilms et al., 2022

Answer 66

• The percentage of calves requiring therapeutic interventions related to diarrhea was greater in WP-fed calves (29%) than HF and HL calves (4%), whereas HP (13%) did not differ with other groups.
• This was coupled with lower blood acid-base, blood gas, and blood sodium in WP than in MR-fed calves.
• Calves fed HF had greater serum nonesterified fatty acids compared with other groups, and greater serum amyloid A compared with WP and HL calves.

Question 67

Potential benefits of early-life supplementation of liquid feed with fennel (Foeniculum vulgare) seeds or oregano (Origanum vulgare) leaves on growth, health, and blood metabolites in Holstein dairy calves.
Ansari et al., 2022

Answer 67

• At weaning, blood concentration of triglycerides was higher in FSP and OLP groups compared with CON group. Supplementation of the liquid feed with FSP or OLP, especially FSP, had beneficial effects on calf growth performance and health

Question 68

Effects of calcareous marine algae on milk production, feed intake, energy balance, mineral status, and inflammatory markers in transition dairy cows
Neville et al., 2022

Answer 68

• These findings demonstrate the benefits of supplementing CMA to dairy cows during the transition period compared with a CON treatment containing limestone as the primary Ca source.

Question 69

Effect of nerve growth factor-β administered
at insemination for lactating Holstein dairy
cows bred after timed-artificial insemination
protocol.
Hubner et al., 2022

Answer 69

The current study revealed that effects to Nerve GF in lactating Holstein cows were minor and contingent with parity for progesterone, and no improvement in ISG relative abundance and P/AI were observed.

Question 70

Associations between anogenital distance and
measures of fertility in lactating North American
Holstein cows: A validation study.
Carrelli et al., 2022

Answer 70

 Anogenital distance had a weak positive association with both parity (r = 0.22) and 305-d ME milk yield (r = 0.04).
 Results indicate an inverse relationship between AGD and measures of fertility in lactating cows, validating our earlier report.

Question 71

Identification and characterization of dairy cows with different backfat thickness antepartum in relation to postpartum loss of backfat thickness: A cluster analytic approach

Riosa et al., 2022

Answer 71

 Overall, OC cows lost more BFT than normal or lean cows. However, those OC cows with a smaller loss of BFT produced less milk than OC cows with greater losses.

Question 72

Effects of a low- or high-frequency colostrum feeding protocol on immunoglobulin G absorption in newborn calves

Lopez et al., 2022

Answer 72

 Conclusion: although LF calves had a greater AUC, HF calves were still able to absorb IgG in the second and third meal, allowing HF calves to achieve serum IgG levels similar to those of LF calves at 24 h.
 Conclusion 2: the provision of 3 meals at 70.5 g/L of IgG within the first 12 h of life did not result in added benefits to serum IgG or AEA levels.

Question 73

Effects of concentrate allowance and individual dairy cow personality traits on behavior and production of dairy cows milked in a free-traffic automated milking system

Schwanke et al., 2022 (Devries last author)

Answer 73

 Despite receiving more AMS concentrate per milking, more fearful cows did not achieve the target concentrate delivery of 6.0 kg/d, and these cows also had less total DMI and greater day-to-day total DMI when allocated more AMS concentrate.

Question 74

The transfer of passive immunity in calves born at pasture

Mason et al., 2022

Answer 74

 For every hour longer postbirth that it took for a calf to have its first suckling event, odds of FPT at d 3 increased by 1.21 times, and compared with calves that only suckled once, calves that suckled 2, 3-5, or >5 times had 0.42, 0.35, and 0.10 times the odds of FPT, respectively.
 Calves that suckled in the paddock and were fed colostrum with ≥22% Brix had the highest STP, and lowest odds of FPT, of any suckling/Brix % combination.
 TREND: STP > in calves that suckled in the paddock and fed <22% Brix compared with calves that did not suckle in the paddock and fed ≥22% Brix.
 Very large between-farm variabilities for rates of suckling, colostrum feeding, and FPT risk.

Question 75

Distribution of staphylococcal and mammaliicoccal species from compost-bedded pack or sand-bedded freestall dairy farms

Adkins et al., 2022

Answer 75

 The prevalence of S. aureus was high in bulk tank milk for all herds, regardless of herd type, which may represent the influence of unmeasured management factors.
 Conclusion: staphylococcal and mammaliicoccal species were highly prevalent among samples from both farm types.

Question 76

Associations of somatic cell count with milk yield and reproductive performance in grazing dairy cows

Rearte et al., 2022

Answer 76

 Conclusion: SCC is negatively associated with the risk for conception and with daily milk yield in grazing dairy cows – higher when > SCC after the service date and it is influenced by severity of mastitis, and in the case of milk yield, the negative association is influenced by parity, milk production quartile, and severity of mastitis.

Question 77

Bayesian estimation of sensitivity and specificity of a rapid mastitis test kit, bacterial culture, and PCR for detection of Staphylococcus aureus, Streptococcus species, and coliforms in bovine milk samples

Chamchoy et al., 2022

Answer 77

 Conclusion: use of the on-farm mastitis test kit could enhance sustainable antimicrobial drug use by rapidly identifying Streptococcus mastitis for targeted treatment.
 Conclusion2: Staph. aureus outbreak where cows can be rapidly screened to identify cases for segregation or culling during an outbreak and kit-negative cows further confirmed by milk culture or qPCR.

Question 78

Effect of plane of nutrition and analgesic drug treatment on wound healing and pain following cautery disbudding in preweaning dairy calves

Reedman et al., 2022

Answer 78

 Conclusion: BN milk feeding program for calves can result in faster healing times and more activity, and that providing an extra NSAID 3 d after disbudding appears to slow the healing process but may result in less pain experienced by the calf 1 to 2 wk after the procedure.
 Conclusion 2: after the complete removal of the horn bud, wounds can take more than 8 weeks to re-epithelize and fully heal.

Question 79

Effect of colostrum on the acute-phase response in neonatal dairy calves

Peetsalu et al., 2022

Answer 79

colostrum cytokines influence calf serum cytokine concentrations. Thus, they influence the newborn calves’ adaptation to the environment and the development of their immune system. Factors that activate an APR during the second and third week of life have a long-term influence on calves’ development.

Question 80

The effect of hides and parity on behavior of periparturient dairy cows at pasture

Jensen et al., 2022

Answer 80

 Conclusion: primiparous cows move further away from herd members at calving than multiparous cows and suggest that primiparous cows prefer to isolate themselves through distance rather than seeking artificial cover.
 Conclusion 2: contrary to expectation, the hides did not make more cows select a calving site away from the feeding area.

Question 81

A systematic review of the cost of ketosis in dairy cattle

Cainzos et al., 2022

Answer 81

the 10 studies reviewed, 9 report cost of a case of ketosis, and the estimates vary widely, with values ranging from €19 to €812. Two studies report ketosis cost at a farm level (€3.6–€29/ cow per year)

Question 82

Using a target trial approach to evaluate the role of hyperketonemia in sole ulcer and white line hoof lesion development

Wynands et al., 2022

Answer 82

 Conclusion: the wide range of compatible causal estimates suggest that hyperketonemia likely has a limited role in the development of SUWL in cows with or without a hoof lesion precalving.

Question 83

Development of a multivariable prediction model to identify dairy calves too young to be transported to auction markets in Canada using simple physical examination and body weight

Buczinski et al., 2022

Answer 83

 The sensitivity of these models to find calves < 9 d old was not to be used for monitoring compliance with the Canadian federal regulation.
 The relatively high model specificity may help to use this model as a rule-in test rather than a rule-out test.

Question 84

Differences in the association of cough and other clinical signs with ultrasonographic lung consolidation in dairy, veal, and beef calves

Lowie et al., 2022 (Pardon last author)

Answer 84

 As a cross-sectional measurement, diagnostic accuracy of spontaneous cough is too low to be used as a criterion to select animals with pneumonia for antimicrobial treatment.
 At the group level, cough monitoring holds potential as an early warning sign, after which lung ultrasonography should follow.
 As a cross-sectional measurement, diagnostic accuracy of spontaneous cough (accuracy = 65.1%, sensitivity = 37.4%, specificity = 85.7%) is too low to be used as a criterion to select animals with pneumonia for antimicrobial treatment. At the group level, cough monitoring holds potential as an early warning sign, after which lung ultrasonography should follow.

Question 85

Suckling behavior of calves in seasonally calving pasture-based dairy systems, and possible environmental and management factors affecting suckling behaviors

Cuttance et al., 2022

Answer 85

 Farm risk factors associated with the HR of suckling: 1) frequency of calf collection (calves that were born on farms that collected calves once a day suckled earlier than calves on farms that removed calves more than once a day); 2) temperature (a minimum temperature of <10°C within 6 h of a calf being born was associated with a 0.69 hazard of suckling in the calving paddock).
 Conclusion: large farm variability

Question 86

Evaluating the effectiveness of a single application of 7% iodine tincture umbilical dip as a prevention of infection of the external umbilical structures in dairy calves

Van Camp et al., 2022

Answer 86

 Conclusion: administering a single application of 7% iodine tincture dip to the umbilicus around the time of birth may not be effective for preventing external umbilical infections. Farm-level management factors, including colostrum management, appear to have more influence on risk of this disease.

Question 87

Daily behavioral measures recorded by precision technology devices may indicate bovine respiratory disease status in preweaned dairy calves

Cantor et al., 2022

Answer 87

 Conclusion: there is the potential to use feeding and activity behaviors to identify BRD development in preweaning calves.
 We suggest relative changes in unrewarded visits may be useful for algorithm development when d -5 is used as a baseline.

Question 88

Toward on-farm measurement of personality traits and their relationships to behavior and productivity of grazing dairy cattle

Neave et al., 2022

Answer 88

 Conclusion: individual differences in daily behavior patterns and milk production of dairy cattle are associated with personality traits of cows, measured using several short behavioral tests.

Question 89

Effects of routine treatment with nonsteroidal anti-inflammatory drugs at calving and when lame on the future probability of lameness and culling in dairy cows: A randomized controlled trial

Wilson et al., 2022 (Bell and Huxley authors)

Answer 89

 Group 1: therapeutic trim and a hoof block on the sound claw (if deemed necessary) every time they were treated for lameness;
 Group 2: same G1 + 3-d course of ketoprofen (single dose daily) every time they were treated for lameness;
 Group 3: same G2 + 3-d course of ketoprofen (single dose daily) starting 24 to 36 h after each calving;
 Group 4: 3-d course of ketoprofen (single dose daily) every time they were identified with lameness. No therapeutic trim was administered to this group, unless they were identified as severely lame (a single score ≥3).

The lameness effect size we identified was large and indicated that treating a cohort of animals with the group 3 protocol, would lead to an absolute reduction in population lameness prevalence of approximately 10% and severe lameness prevalence of 3%, compared with animals treated in accordance with conventional best practice (group 1).

Question 90

Development and evaluation of a Mycobacterium bovis interferon- enzyme-linked immunospot (ELISpot) assay for detection of bovine tuberculosis

Li et al., 2022

Answer 90

 M. bovis IFN- ELISpot assay we established could detect infected cattle earlier than the BOVIGAM ELISA test.
 In conclusion, the present study confirms the potential application of the M. bovis IFN-γ ELISpot assay for the diagnosis of bTB in dairy farms by using 2 strains of BoIFN-γ mAb and specific antigen CE protein

Question 91

Heritability of subclinical endometritis in Norwegian
Red cows.
Diaz-Dundahl et al., 2022

Answer 91

• A cut-off level of 5% PMN has been established as a general threshold for the definition of SCE in earlier literature.
• Different trait definitions were examined, and SCE was defined as binary traits, based on the following cut-off levels of PMN: Cyto0 = PMN >0, Cyto3 = PMN >3%, Cyto5 = PMN >5%, Cyto10 = PMN >10%, and Cyto20 = PMN >20%.
• The only trait definition that had an estimated genetic variance larger than the standard error was Cyto5, with an estimated heritability of 0.04. For all other definitions, the genetic variance was not significantly different from zero.
• the current study indicates that SCE is heritable at a similar level to that of clinical endometritis and metritis, and has potential as a future fertility phenotype to be used for breeding purposes.

Question 92

An examination of labor time-use on spring
calving dairy farms in Ireland.
Hogan et al., 2022

Answer 92

• The next 5 most time-consuming tasks were calf care (14%), grassland management (13%), cow care (10%), repairs and maintenance (10%), and administration/business (8%).

Question 93

Implementation of compact calving at the farm level: A qualitative analysis of farmers operating pasture-based dairy systems in Ireland
Mulkerrins et al., 2022 (McAloon middle author)

Answer 93

• In Ireland, where pasture-based systems are dominant, a key performance indicator that reflects the degree of compact calving is referred to as 6-wk calving rate (6-wk CR). Although the industry target is 90%, the national average 6-wk CR in Ireland is currently 67%.
• The findings of this study identify complexities and challenges at farm level when it comes to increasing 6-wk CR, such as increased workload and challenges associated with large numbers of male calves born during a condensed calving season.
• Benefits experienced by farmers as a result of increasing 6-wk CR included increased days in milk and consequently improved cash flow as well as increased grass utilization.

Question 94

Effects of feeding 25-hydroxyvitamin D3 with an acidogenic diet during the prepartum period in dairy cows: Mineral metabolism, energy balance, and lactation performance of Holstein dairy cows

Silva et al. 2022

Answer 94

• Feeding 25(OH)D3 increases milk yield, 3.5% fat-corrected milk, and energy-corrected milk and improves milk yield components in early lactation.
• Overall, these findings suggest that 25(OH)D3 at 3 mg/d can improve the energy metabolism and lactation performance, compared with the current-feeding practice of supplementing vitamin D3 at 0.625 mg/d.

Question 95

Effects of prepartum metabolizable protein
supply and management strategy on lactational
performance and blood biomarkers in dairy
cows during early lactation.
Zang et al., 2022

Answer 95

• Dry matter intake for wk 1 to 12 postpartum did not change for LPHP versus LPLP or for SDHP versus LPLP.
• Compared with LPLP cows, LPHP cows had lower energy-corrected milk yield and tended to have decreased milk fat yield during wk 1 to 12 of lactation.

Question 96

Evaluation of luteolysis, follicle size, and time
to ovulation in Holstein heifers treated with two
different analogs and doses of prostaglandin-F2α.
Umana Sedo et al., 2022

Answer 96

 Type of PGF2α did not affect progesterone concentrations past 36 h from treatment; however, heifers treated with 2 PGF2α injections had lesser progesterone concentrations and CL blood flow from 36 to 72 h after treatment compared with heifers that received a single PGF2α injection

Question 97

A high-concentrate diet induces an inflammatory response and oxidative stress and depresses milk fat synthesis in the mammary gland of dairy cows

Ma et al.2022

Answer 97

 Conclusion: HC diet can induce SARA with increased concentration of LPS in the peripheral vein, stimulate inflammatory reactions and oxidative stress, and inhibit milk fat synthesis in the mammary gland of dairy cows.

Question 98

Reproductive tract disease in Irish grazing dairy cows: Retrospective observational study examining its association with reproductive performance and accuracy of 2 diagnostic tests

Kelly et al.(McAloon author)

Answer 98

 Conclusion: higher scores in both tests were associated with impaired fertility, and UE scoring with a threshold of ≥1 had the highest test Se and Sp estimates although test Se was conditional on days in milk when the PBE occurred

Question 99

First test-day postcalving risk factors for clinical mastitis in southern Chile dairy farms: A retrospective cohort study

Astorga-Jorquera et al.2022

Answer 99

 Days in milk, fat, urea, parity, season, and somatic cell counts – associated with clinical mastitis in the first 200 d in milk.
 Cows > milk yield, parity, urea, and somatic cell count > odds of being diagnosed with clinical mastitis.
 > milk fat < odds of clinical mastitis.

Question 100

Retention of internal teat sealants over the dry period and their efficacy in reducing clinical and subclinical mastitis at calvings

Bates et al. 2022

Answer 100

 Conclusion: both products had equivalent efficacy for SCM and CM. As the quantity of residual increased, the difference in residual weight recovered increased but this may represent increases in debris rather than indicating a more effective barrier.

Question 101

Dynamics of automatically generated body condition scores during early lactation and pregnancy at first artificial insemination of Holstein cows.
Pinedo et al., 2022

Answer 101

• Overall, low BCS and more pronounced reductions in BCS occurring closer to first artificial insemination resulted in lower odds of pregnancy per artificial insemination.

Question 102

Efficacy of bacteriocin-based formula for reducing
staphylococci, streptococci, and total bacterial counts on teat skin of dairy cows.
Bennett et al., 2022

Answer 102

• Thus, nisin and the bacteriocin consortium showed the most promise as a teat disinfectant by reducing staphylococci, streptococci, and total bacteria counts.

Question 103

Buffering lidocaine heightens aversion to cornual
nerve injections in dairy calves.

Adcock and Tucker, 2022

Answer 103

• Female Holstein calves were assigned to 1 of 3 treatments:
  1. cornual nerve blocks with 5.5 mL of unbuffered lidocaine (n = 9),
  2. buffered lidocaine (n = 9), or
  3. sham procedure with no needle inserted (n = 9).
• Contrary to our hypothesis, struggling was most marked in calves that received buffered lidocaine.
• Similarly, calves administered unbuffered or buffered lidocaine had elevated heart rates for 1 or 3 min after the first injection, respectively, compared with at the end of the 5-min observation period. Calves in the buffered treatment had lower eye temperatures in the first half of the observation period compared with the second half, consistent with responses cattle show to other aversive procedures, but no changes over time were observed in the other 2 treatments.
• We detected no treatment differences in heart rate variability measures. These results suggest that cornual nerve blocks are aversive, at least in the short term, and that buffering the lidocaine worsens the calf’s response to this procedure.

Question 104

Heat stress during the transition period is associated
with impaired production, reproduction,
and survival in dairy cows.

Menta et al., 2022

Answer 104

• Postpartum HS was associated with an increase of 6.3 % in incidence of metritis and tended to be associated with an increase of 1.9 % in mastitis incidence compared with POST TN

Question 105

Effects of provision of drinking water on the behavior and growth rate of group-housed calves with different milk allowances.

Lowe et al., 2022

Answer 105

The provision of drinking water was associated with a greater proportion of observations eating hay but less eating calf starter.
The increase in the proportion of observations eating calf starter with age was greater for calves on a low milk allowance than of those provided a high milk allowance; this is likely due to calves on a low milk allowance searching for nutrients and energy.

Question 106

Hay provision affects 24-h performance of normal
and abnormal oral behaviors in individually
housed dairy calves.

Downey et al., 2022

Answer 106

• During weaning, hay calves tended to consume increasingly more total mixed ration, significantly more water, and less grain than control calves.
• Hay calves also spent less time self-grooming (12% vs. 14%), tongue flicking (14% vs. 18%), and performing NNOM (17% vs. 21%) than control calves.
• Overall, we found that hay provision affected most oral behaviors that calves perform; it promoted natural feeding behaviors and reduced abnormal ones, suggesting hay should be provided.

Question 107

Effects of restricted dietary phosphorus supply
during the dry period on productivity and
metabolism in dairy cows.

Wächter et al., 2022 (Grunberg last author)

Answer 107

• The results reported here indicate that restricted dietary P supply during the dry period positively affected the Ca homeostasis of periparturient dairy cows but did not reveal negative effects on DMI, milk production, or metabolic activity in the following lactation. Restriction of P during the dry period was associated with hypophosphatemia antepartum but neither exacerbated postparturient hypophosphatemia, which is commonly observed in fresh cows, nor was associated with any clinical or subclinical

Question 108

Effects of bovine casein hydrolysate as a dry cow therapy on prevention and cure of bovine intramammary infection, milk production, and
somatic cell count in the subsequent lactation.
Shoshani and van Straten, 2022

Answer 108

• Incidence of stillbirth, clinical mastitis, retained placenta, endometritis (5 to 12 d postcalving), ketosis, abortions, and reproduction did not differ between the 2 groups.
• Results suggest that a single intramammary administration of bCNH at dry-off effectively increases milk yield and lowers SCC, prevents new IMI during the dry period, and may be a beneficial alternative for curing existing IMI at dry-off, mainly by CNS.

Question 109

Reducing milking frequency from twice each
day to three times each two days affects protein
but not fat yield in a pasture-based dairy
system.
Edwards et al., 2022

Answer 109

• Milking 3 times in 2 d (3-in-2) could enhance the attractiveness of the dairy workplace relative to twice-a-day milking (TAD) by reducing labor requirements for milking and increasing workforce flexibility.
• For the proportion of the season milked 3-in-2, there was a significant effect on milk (−11%), protein (−8%), and lactose (−12%) yield per cow per year, but no effect of fat.

Question 110

Access time to pasture under wet soil conditions:
Effects on productivity and profitability
of pasture-based dairying.
Fenger et al., 2022

Answer 110

• Less time spent at pasture under wet soil conditions lowered treading damage but had no effect on annual pasture production (mean 14.8 t of organic matter/ha).
• Annual milk solids production per cow was lowest for the control herd (485 kg) and not different between the other systems (503 kg).
• Reducing treading damage to swards did not improve productivity or profitability of the grazing systems.

Question 111

Effects of dietary butyrate supplementation and
oral nonsteroidal antiinflammatory drug administration
on serum inflammatory markers and
productivity of dairy cows during the calving
transition.
Engelking et al., 2022

Answer 111

• Dietary butyrate supplementation and oral NSAID administration did not have overall positive effects on production performance of dairy cows during the calving transition period.

Question 112

Revenues and costs of dairy cows with different voluntary waiting periods based on data of a randomized control trial
Burgers et al. 2022

Answer 112

• .
• Total yearly costs were also greater in VWP50 compared with VWP200 (€1,964 vs. €1,729), mainly because of €102 greater concentrate costs.
• The VWP was not significantly associated with the NPCF per cow per year.
• A change in milk, feed, or calf price, or a change in labor costs for calving cows or for inseminations had a greater effect on the yearly NPCF of cows in VWP50 compared with cows in VWP200.

Question 113

Effects of prepartum supplementation of β-carotene in Holstein cows
Prom et al., 2022

Answer 113

• In conclusion, in pregnant cows already receiving adequate vitamin A but with low serum β-carotene concentration, supplementation of β-carotene increased concentrations of β-carotene and vitamin A in blood serum, but did not affect production, reproduction, or health

Question 114

Performance and visceral tissue growth and development of Holstein calves fed differing milk replacer allowances and starch concentrations in pelleted starter
Yohe et al., 2022

Answer 114

• The length, width, and 2-dimensional area of rumen papillae were also increased in low- (area: 0.88 ± 0.03 mm2) compared with high-MRA (0.46 ± 0.03 mm2) calves. The majority of differences were attributed to increased MR allowance, which contributed to reduced pelleted starter intake by more than 50% and reduced rumen development, whereas differences in starch intake from the completely pelleted starter had minimal effects on overall growth and tissue measurements

Question 115

Streptococcus dysgalactiae ssp. dysgalactiae in Norwegian bovine dairy herds: Risk factors, sources, and genomic diversity.
Smistad et al., 2022.

Answer 115

• Risk factors for high incidence of SDSD-IMI in freestall dairy herds were related to housing, including closed flooring in alleys and rubber mats in cubicle bases.
• Parlor milking was also a risk factor compared with automatic milking systems.
• From herd visits, a considerable proportion of extramammary samples were SDSD positive, particularly from wounds and skin of the animals and the cubicle bases. Samples from mucous surfaces (nostrils, rectum, and vagina) and water troughs were least frequently positive.
• No significant association was identified between sampling site (milk, body sites, and environment) and SDSD sequence types.

Question 116

Cattle farmer psychosocial profiles and their association with control strategies for bovine viral diarrhea.
Prosser et al., 2022 (Green author)

Answer 116

• In conclusion, farmer psychosocial factors were associated with strategies for BVD control in UK cattle farmers. Psychological proximity to veterinarians was a novel factor associated with proactive BVD control and was more important than the more extensively investigated trust

Question 117

Effect of dry-off management on milking behavior, milk yield, and somatic cell count of dairy cows milked in automated milking systems.

France et al., 2022 (Dufor , Barkema, Devries)

Answer 117

Overall, these data suggest that reducing both milking frequency and feed quantity in the AMS is the most efficient method to decrease milk yield before dry-off, without negatively influencing milking frequency or yield in the next lactation, as well as without affecting milk quality

Question 118

The effect of transdermal flunixin meglumine on blood cortisol levels in dairy calves after cautery disbudding with local anesthesia.
Röder et al., 2022

Answer 118

• There was no statistical difference between average daily weight gain and the treatment procedure. Total lying time was not affected by treatment after disbudding.
• In conclusion, transdermal flunixin meglumine given at the time of disbudding combined with local anesthesia decreased concentrations of the stress biomarker cortisol, but a second dose 6 h after disbudding had no further effect on plasma cortisol levels.

Question 119

Heat treatment of colostrum at 60°C decreases colostrum immunoglobulins but increases serum immunoglobulins and serum total protein: A meta-analysis.
Malik et al., 2022

Answer 119

• The heat treatment of colostrum was also associated with a significant increase in STP by 0.21 g/dL for LT (95% CI = 0.07–0.35).
• In conclusion, the present work demonstrated that the heat treatment of colostrum ≤60°C decreased colostrum IgG by 5.38 g/L for LT and increased serum IgG by 2.65 g/L and STP by 0.21 g/dL.

Question 120

The effect of environmental temperature on
average daily gain in preweaned calves: A randomized
controlled trial and Bayesian analysis.
Hyde et al., 2022 (Hudosn & Green)

Answer 120

• 4 groups: no jacket and no heat lamp, heat lamp but no jacket, jacket but no heat lamp, or both heat lamp and jacket
• Calves housed under a 1-kW heat lamp had an increased ADG of 0.09 kg/d (95% bootstrap confidence interval: −0.02 to 0.20 kg/d),
• and no effect of jacket or interactions between jacket and heat lamp were found.
• A significant positive association was identified between the mean environmental temperature of the calf building and ADG, with a 1°C increase in temperature being associated with a 0.03 kg/d increase in ADG (95% bootstrap confidence interval: 0.01 to 0.04 kg/d).
• This study demonstrated that a 1-kW heat lamp was effective in increasing ADG in calves, and no significant effect of calf jacket on ADG was found.
• A significant, positive effect of increased pen temperature on calf ADG was identified in this study and was reinforced when including prior information from previous research within a Bayesian framework

Question 121

Economics of timed artificial insemination with unsorted or sexed semen in a high-producing, pasture-based dairy production system.

Walsh et al., 2022

Answer 121

• Sensitivity analysis showed that when hormone costs increased by €10/cow TCONV-H and TSEX-HC had a 38 and 23% chance, respectively, of not returning a positive annual profit advantage.

Question 122

Assessment of the main pathogens associated with clinical and subclinical endometritis in cows by culture and MALDI-TOF mass spectrometry identification

Paiano et al., 2022

Answer 122

 Some anaerobic species were exclusively isolated from the CE group, even though they presented lower frequency.
 18.1% of samples from CE cows and 40% of SCE cows were negative to bacterial isolation

Question 123

Estimating the nonlinear association of online somatic cell count, lactate dehydrogenase, and electrical conductivity with milk yield

Bonestroo et al. 2022

Answer 123

 Having chronic mastitis decreased milk synthesis rate in all models.
* The identified nonlinearities between mastitis indicators and milk synthesis rate should be incorporated in statistical models for more accurate estimations of milk loss due to mastitis.

Question 124

Replacing concentrates with a high-quality hay
in the starter feed of dairy calves: II. Effects on
the development of chewing and gut fermentation,
and selected systemic health variables.

Poier et al., 2022

Answer 124

• In conclusion, feeding high-quality hay, instead of concentrate-rich starter feeds, resulted in improved rumination and ruminal fermentation profile, without affecting ruminal pH and systemic and stress health variables.

Question 125

Repeatability of anogenital distance measurements from birth to maturity, and at different physiological states in female Holstein cattle.
Rajesh et al., 2022

Answer 125

AGD measured at birth did not reflect AGD at breeding age in heifers, but AGD measurements in cows had high repeatability at all stages of the estrous cycle, gestation, and lactation, except at 270 d of gestation. Therefore, AGD could be measured reliably at any of the aforesaid physiological states in cows due to its high repeatability, except during late gestation

Question 126

Temporal profiles describing markers of inflammation and metabolism during the transition period of pasture-based, seasonal-calving dairy cows.

Spaans et al., 2022

Answer 126

• Our results indicate that moderate-yielding dairy cows undergo similar homeorhetic changes to high-yielding housed cows; however, differences in diet composition result in greater BHB concentrations than expected, based on their milk production and NEFA concentrations

Question 127

Accessory corpus luteum induced by human chorionic gonadotropin on day 7 or days 7 and 13 of the estrous cycle affected follicular and luteal dynamics and luteolysis in lactating Holstein cows.

Cunha et al., 2022

Answer 127

• Cows with typical cycles treated with hCG (hCG7 and hCG7+13) had a later onset of luteolysis, prolonged time to undergo complete luteolysis, and greater proportion of cows with 3 follicular waves than CON, resulting in a longer interovulatory interval for hCG7 and hCG7+13 than CON

Question 128

Simulation of feed restriction and fasting: Effects
on animal recovery and gastrointestinal
permeability in unweaned Angus-Holstein
calves.

Pisoni et al.,2022

Answer 128

• BW was greater for the CT treatment compared with the others from d 0 to d 7, whereas BW of SV was lesser compared with the others from d −1 to d 7. No differences among treatments were observed at weaning.
• Similarly to BW, no differences in concentrate intake among treatments were observed at weaning on d 42 of the study.

Question 129

Preweaning dairy calves’ preferences for outdoor
access.

Whalin et al., 2022

Answer 129

• These results indicate that, when given the option in the summer, calves make use of an outdoor space, but this appears to vary with weather, calf age, average daily gain, and coat color

Question 130

Bacteriological outcomes following random allocation to quarter-level selection based on California Mastitis Test score or cow-level allocation based on somatic cell count for dry cow therapy.

McDougall et al., 2022

Answer 130

• Apparent bacteriological cure proportion for any IMI was higher in quarters assigned to the CMT than the SCC-group (349/368 (0.95, 95% CI 0.92–0.97) versus 313/346 (0.90, 95% CI 0.87–0.93)).
• New IMI proportion was lower among quarters assigned to the CMT than SCC-group [101/3,212 (0.032, 95% CI 0.025–0.038) versus 142/3,232 (0.044, 95% CI 0.036–0.051)].
• There was no difference in incidence of clinical mastitis between treatment groups.
• The total mass of antimicrobials used was 63% higher in the CMT-group than in the SCC-group (3.47 versus 2.12 mg/kg of liveweight

Question 131

Replacing concentrates with a high-quality
hay in the starter feed in dairy calves: I. Effects
on nutrient intake, growth performance,
and blood metabolic profile.

Terler et al., 2022

Answer 131

• In conclusion, feeding high-quality hay can fully replace starter concentrates in the feeding of dairy calves without adverse effects on performance during the rearing period, while increasing forage fiber intake and utilization, which enhanced ruminal ketogenesis and cholesterogenesis around weaning.

Question 132

First-milking colostrum mineral concentrations and yields: Comparison to second milking and
associations with serum mineral concentrations, parity, and yield in multiparous Jersey cows.
Valldecabres and Silva-del-Río, 2022

Answer 132

• Serum and first-milking colostrum Cu concentrations were positively associated, but no significant associations were observed between other minerals’ serum and first-milking colostrum concentrations or total yields.
• Parity was associated with first-milking colostrum Ca, P, K, and Fe concentrations and yields; younger multiparous cows had higher concentrations and total yields of these minerals.
• Mineral total yields were linearly associated with first-milking colostrum yield
• In conclusion, variation in first-milking colostrum mineral concentrations and total yields across cows could be partially explained by cow parity and colostrum yield.

Question 133

Effects of compound probiotics on growth performance, rumen fermentation, blood parameters, and health status of neonatal Holstein calves
Wang et al., 2022

Answer 133

• Diet supplemented with compound probiotics improved the health status of calves, indicated by the decreased fecal score at 3 wk of age and the medicine usage.

Question 134

Impact of gonadotropin-releasing hormone administration at the time of artificial insemination on conception risk and its association with oestrous expression
Burnett et al., 2022

Answer 134

 Cows with greater estrous expression had greater pregnancy per AI than those with lesser expression
 GnRH administration was found to increase fertility in cows with reduced estrous expression but not for those with greater intensity of estrous expression
 Increased ovulation rates do not seem to be the direct mechanism behind this relationship

Question 135

Effects of increasing air temperature on physiological and productive responses of dairy cows at different relative humidity and air velocity levels
Zhou et al., 2022

Answer 135

 Relative Humidity and Air Velocity significantly affected the responses of RR, rectal temperature and skin temperature, and productive performance of high-producing Holstein cows.
 These responses already occurred at moderate ambient T of 19 to 26°C

Question 136

Estrous activity in lactating cows with divergent genetic merit for fertility traits
Reed et al., 2022

Answer 136

 Cows with positive genetic merit for fertility traits had longer and more active estrous events, but the inter-estrous interval did not differ between the 2 groups.
 The first postpartum estrous event was associated with less activity and was shorter than subsequent estrous events in both fertility groups.

Question 137

Use of ATP luminometry to assess the cleanliness of equipment used to collect and feed colostrum on dairy farms
Buczinski et al., 2022 (Roy Middle author)

Answer 137

 Punctual assessment of colostrum harvest and feeding equipment cleanliness by luminometry can be useful to differentiate herds according to their hygiene and health characteristics.
 The maximal dichotomized luminometry value (<1,000 RLU or ≥1,000 RLU) was associated with hygiene and health dimension.

Question 138

Single-dose meloxicam treatment improves standing ability of low-vitality dairy calves

Kovacs et al., 2022

Answer 138

 A single-dose meloxicam treatment showed considerable promise for improving standing ability of low-vitality calves.
 Latency and the first attempt to stand were not influenced by the NSAID treatment; however, the time spent standing, the longest standing bout, and the average duration of standing indicated increased standing ability of meloxicam-treated calves with low vitality, but not in normal-vitality calves.

Question 139

Effect of bupivacaine liposome suspension administered as a cornual nerve block on indicators of pain and distress during and after cautery dehorning in dairy calves
Martin et al., 2022

Answer 139

 Bupivacaine liposome suspension as a cornual nerve block at the time of dehorning was as effective at controlling pain as a multimodal approach of lidocaine and meloxicam
 At 4 h and 24 h after dehorning, the LID + MEL group had a lower average prostaglandin E2 metabolites concentration compared with all other treatment group

Question 140

Management-related factors in dry cows and their associations with colostrum quantity and quality on a large commercial dairy farm
Borchardt et al., 2022

Answer 140

Colostrum quantity:
 Primiparous cows: Affected by month of calving, sex of the calf, stillbirth
 Multiparous cows: Affected by month of calving, calving ease, sex of the calf, previous lactation MY, days spent in the far off group, days in the close up pen
Colostrum quality:
 Primiparous cows: Affected only by month of calving
 Multiparous cows: Affected by parity, month of calving, milk yield, colostrum quantity

Question 141

Randomized clinical trial to evaluate the effects of a prepartum cholecalciferol injection on postpartum serum calcium dynamics and health and performance in early-lactation multiparous dairy cows
Venjakob et al., 2022

Answer 141

 BUT injection of 12 × 106 IU of cholecalciferol had a negative effect on inflammatory response, milk production in early lactation, and ultimately on reproductive performance.

Question 142

Feeding an acetate-based oral electrolyte reduces the ex vivo Escherichia coli growth potential in the abomasum of calves fed oral electrolytes alone or 30 minutes following a milk feeding compared with feeding a bicarbonate-based oral electrolyte
Kasi et al., 2022

Answer 142

 Feeding a sodium acetate-based oral electrolyte solution limited the increase in abomasal pH and ability of E. coli to grow in abomasal contents, regardless of whether the calves were fed oral electrolytes alone or 30 min after a milk feeding.

Question 143

Reduced liner-open phase and vacuum instead of prestimulation increase parlor efficiency in dairy cows
Tuor et al., 2022

Answer 143

shortening prestimulation to a 5-s teat cleaning followed by a latency period and milking at regular vacuum and pulsation did not represent an adequate duration of prestimulation and is not adequate to save occupancy time.

Question 144

Calf and dam characteristics and calf transport age affect immunoglobulin titers and hematological parameters of veal calves

Marcato et al., 2022

Answer 144

 Calves transported at 28 d of age had a lower probability of individual treatments with medicines other than antibiotics (e.g., anti-inflammatories, multivitamins, and anti-coccidial drugs), a lower mortality risk, and a higher carcass weight than calves transported at 14 d of age.

Question 145

Cow- and herd-level risk factors for lameness in partly housed pasture-based dairy cows
Browne et al., 2022

Answer 145

 Cow-level risk factors for increased lameness prevalence were age and genetic predicted transmitting ability for lameness.
 Herd-level risk factors included farm and herd size, stones in paddock gateways, slats on cow tracks near the collecting yard, a sharper turn at the parlor exit, presence of digital dermatitis on the farm, and the farmers’ perception of whether lameness was a problem on the farm

Question 146

Reducing milking frequency from twice to once daily as an adjunct treatment for ketosis in lactating dairy cows—A randomized controlled trial
Williamson et al., 2022 (author Duffield, LeBlanc)

Answer 146

 In conclusion, a 2-wk reduction of MF in ketotic cows from twice to once daily with treatment with PG resolved ketosis and decreased blood BHB concentrations more effectively than treating TDM cows with PG alone. However, the 2-wk MF reduction had immediate and long-term (up to 13 wk after cessation of MF reduction) negative effects on milk production

Question 147

Selective dry cow therapy effect on milk yield and somatic cell count: A retrospective cohort study
Niemi et al., 2022

Answer 147

 For a cow likely to have intramammary infection, a missed aDCT treatment undesirably affects subsequent lactation milk yield and somatic cell count.
 For cows with an SCC of 200,000 cells/mL before dry-off, compared with untreated cows, aDCT-treated cows produced 0.97 kg/d more milk and, at 45 DIM, had an SCC that was 20,000 cells/mL lower

Question 148

The influence of personality and weaning method on early feeding behavior and growth of Norwegian Red calves
Whalin et al., 2022

Answer 148

 Calves that were more playful/exploratory consumed more milk per day preweaning and more concentrate per day over the experimental period.

Question 149

Birth conditions affect the longevity of Holstein offspring
Dallago et al., 2022

Answer 149

 Calving ease, calf size, and twinning greatly affected offspring longevity

Question 150

Influence of environmental factors and parity on milk yield dynamics in barn-housed dairy cattle
Marumo et al., 2022

Answer 150

 Prolonged high temperatures over a few days were more important than short-term (temporary) high temperatures over 1 or 2 days.

Question 151

Metabolic and blood acid-base responses to prepartum dietary cation-anion difference and calcium content in transition dairy cows
Zhang et al., 2022

Answer 151

 Feeding a prepartum negative DCAD diet altered blood acid-base balance and induced metabolic acidosis at calving, and improved protein and lipid metabolism.
 Supplementation of high Ca in the negative DCAD diet prepartum was more favorable to metabolic adaptation to lactation in dairy cows than the negative DCAD diet with low Ca.

Question 152

Effect of milk replacer feeding rate and frequency of preweaning dairy calves in the southeastern United States: Glucose metabolism
Orellana Rivas et al., 2022

Answer 152

 MR feeding frequency significantly affects glucose metabolism in the calf, which, however, did not seem to affect body growth.

Question 153

Effects of milk replacer feeding rate and frequency of preweaning dairy calves in the southeastern United States: Performance, abomasal emptying, and nutrient digestibility
Orellana Rivas et al., 2022

Answer 153

 Increasing feeding frequency accelerated abomasal emptying and might reduce heat load of preweaning dairy calves

Question 154

Milk feeding level and starter protein content: Effects on growth performance, blood metabolites, and urinary purine derivatives of Holstein dairy calves
Kazemi-Bonchenari et al., 2022

Answer 154

 Greatest growth in calves fed high milk, and high CP%.
 Feeding starters with a higher proportion of CP may help maintain a more balanced ratio of CP to ME during high milk feeding, to avoid protein deficiency due to low starter intake.

Question 155

Physiological adaptations in early-lactation cows result in differential responses to calcium perturbation relative to nonlactating, nonpregnant cows
Connelly et al., 2022

Answer 155

 Early-lactation cows have more robust responses to calcemic perturbation (i.e. were better at maintaining eucalcaemia) and have increased circulating and mammary serotonin content relative to nonlactating counterparts, while also indicating that serotonin does not directly respond to decreased blood calcium concentrations.
 Collectively, our data demonstrate the differential physiological responses of nonlactating, nonpregnant and early-lactation cows during calcium perturbation and offer insight into the role of serotonin and parathyroid hormone-related protein during lactation.

Question 156

Effects of progesterone concentrations and follicular wave during growth of the ovulatory follicle on conceptus and endometrial transcriptome in dairy cows
Bisinotto et al., 2022

Answer 156

 Follicular wave and progesterone concentration during follicle growth did not affect the signal for maternal recognition of pregnancy (uterine interferon tau), conceptus length, or gene expression measured in conceptuses and endometrium of pregnant cows on d 17 of gestation

Question 157

Effect of gonadotropin-releasing hormone administered at the time of artificial insemination for cows detected in oestrus by conventional oestrus detection or an automated activity-monitoring system
Hubner et al., 2022

Answer 157

 GnRH did not improve ovulation rates, progesterone level 7 d after insemination, or pregnancy outcomes on any of the farms

Question 158

Prevalence and predictors of bacteremia in dairy calves with diarrhoea
Garcia et al., 2022

Answer 158

 Bacteremia was substantially more common in calves with depression and fever (T>39.7C).
 Bacteremia was rare among calves without observed depression.
 Antimicrobial therapy targeting bacteremia is not currently justified in routine cases of diarrhoea in preweaning calves without signs of depression

Question 159

Farm-level factors associated with lameness prevalence, productivity, and milk quality in farms with automated milking systems
Matson et al., 2022 (devires last author)

Answer 159

• Severe lameness occurrence (farms with any cows with locomotion score ≥4) was associated with a greater proportion of underconditioned cows and in farms with stalls with greater curb heights.
• The results highlight the importance of minimizing lameness prevalence, using sand bedding, ensuring adequate feed access and feed bunk space, and ensuring proper cow body condition to optimize herd-level productivity and milk quality in automated milking herds.

Question 160

Improving growth rates in preweaning calves on dairy farms: A randomized controlled trial
Hyde et al., 2022 (Hudson, Green, Down

Answer 160

• Model predictions suggest that a farm with the highest number of interventions in place (15) compared with farms with the lowest number of interventions in place (4) would expect an improvement in growth rates from 0.65 to 0.81 kg/d for MB, from 0.73 to 0.88 kg/d for DH, a decrease in mortality rates from 10.9% to 2.8% in MB, and a decrease in diarrhea rates from 42.1% to 15.1% in DH

Question 161

Effects of restricted dietary phosphorus supply to dry cows on periparturient calcium status
Watchter et al., 2022

Answer 161

2 treatment groups fed prepartum (same adequate P = 0.46% P in DM after calving)
 Low P = 0.16% P in DM
 Adequate P = 0.30% P in DM
Restriction of the phosphorus supply limited to the last 4 wk of pregnancy is sufficient to mitigate the risk of hypocalcemia around parturition, through mechanisms primarily driven by increased bone tissue mobilization.

Question 162

Minimum inhibitory concentrations of chlorhexidine- and lactic acid-based teat disinfectants: An intervention trial assessing bacterial selection and susceptibility

Schwenker et al., 2022

Answer 162

 Although both teat disinfectants were basically effective, isolates differed in their susceptibility to both teat disinfectants.
 Populations of CNS, Staphylococcus aureus, and Corynebacterium spp. showed significantly lower absolute MIC values for chlorhexidine.
 Compared with other species, Corynebacterium spp. showed the lowest susceptibility to either disinfectant

Question 163

Individual and environmental factors associated with defecation while lying down in dairy cows
Foris et al., 2022

Answer 163

 Cows in later stages of pregnancy were less likely to defecate whilst lying in the stall,, with no effect of weight, parity, age, or lameness.
 Also, the more time that cows spent lying down, the greater the likelihood of the defecation whilst lying in the stall, but the cow-to-stall ratio had no effect.

Question 164

M-score and wound healing assessment of 2 nonantibiotic topical gel treatments of active digital dermatitis lesions in dairy cattle

Vanhoudt et al., 2022

Answer 164

 Lesions treated with the enzyme alginogel had a decreased adjusted odds ratio for M-score improvement (aOR: 0.04; 95% confidence interval: 0.01-0.11). Lesions treated with the coppergel mostly transitioned to chronic lesions, whereas lesions treated with the enzyme alginogel mostly remained active lesions.
 The wound healing progress of almost 70% of the lesions treated with coppergel could not be scored, for the greater part due to the presence of crust materials. With these unscorable lesions classified as “improved,” there was no treatment effect on wound healing progress (aOR: 0.99; 95% confidence interval: 0.34-3.05), whereas with unscorable lesions classified as “not improved,” the enzyme alginogel outperformed the coppergel with regard to wound healing progress (aOR: 2.48; 95% confidence interval: 1.07-5.79).
 None of the products used in our study achieved high cure rates (transition to the M0 stage) for active DD lesions

Question 165

Cytological endometritis diagnosis in primiparous versus multiparous dairy cows
Druker et al., 2022

Answer 165

Different criteria should be used for optimal CEM diagnosis in primiparous versus multiparous cows (% PMN threshold; sampling time in lactation)
 Primiparous cows at 30–40 DIM, using a threshold of ≥7%PMN
 Multiparous cows at 60–70 DIM, using a threshold of ≥4%PMN

Question 166

Feeding fennel (Foeniculum vulgare) seed as a potential appetite stimulant for Holstein dairy calves: Effects on growth performance and health
Nowroozinia et al., 2022

Answer 166

 feeding 3 g/d of FSP may be more beneficial in improving the weight gain and skeletal growth (heart girth and hip width) and in reducing the susceptibility to and duration of diarrhoea and pneumonia in dairy calves

Question 167

Effects of small milking stalls on stress responses in dairy cows during milking in group milking parlors
Gomez et al., 2022

Answer 167

 Very small stalls caused changes in behaviour (latency to entering the parlor) and total milk yield
 The first cow per milking batch required more time (on average >40 s) to enter very small stalls

Question 168

Effects of postpartum milking strategy on plasma mineral concentrations and colostrum, transition milk, and milk yield and composition in multiparous dairy cows
Valldecabres et al., 2022

Answer 168

 Compared with twice-a-day milking, plasma calcium concentration was higher for delayed-milking and tended to be higher for restricted-milking cows without negatively affecting future milk yield or composition; however, delaying milking resulted in an inadequate supply of good-quality colostrum.

Question 169

Within-herd prevalence threshold for the detection of Mycobacterium avium ssp. paratuberculosis antibody–positive dairy herds using pooled milk samples: A field study
Krieger et al., 2022

Answer 169

 The pool-milk sampling strategy seems well suited to distinguish between herds with a MAP-Ab-WHPapp ≥ 5% and herds with a MAP-Ab-WHPapp <5%

Question 170

Development of ruminating behaviour in Holstein calves between birth and 30 days of age
Wang et al., 2022

Answer 170

 Overall, to the best of our knowledge, this is the first study that has analyzed the correlation between AFR and other indicators. We found that earlier AFR was associated with shorter duration of non-nutritive oral behavior, longer durations of rumination and eating the bedding, and higher feed intake by 30 d of age.

Question 171

Effect of feeding single-dam or pooled colostrum on maternally derived immunity in dairy calves
Bobbo et al., 2022

Answer 171

 Mean calf serum IgG concentration was lower for calves fed pooled colostrum compared with those that received colostrum from a single cow.

Question 172

Genomic loci and genetic parameters for uterine diseases in first-parity Holstein cows and associations with milk production and fertility
May et al., 2022

Answer 172

 Heritabilities were close to zero
 15 SNPs associated with UD were identified.

Question 173

Comparison of microbiota of recycled manure solids and straw bedding used in dairy farms in eastern Canada
Beauchemin et al., 2022

Answer 173

 Unused RMS generally contained higher bacterial counts than did unused straw
 Klebsiella spp, Salmonella spp, and L. monocytogenes were more frequently detected in unused RMS
 Overall, animal and human pathogens were found in greater numbers and more frequently in unused RMS than unused straw

Question 174

The effect of Holstein-Friesian, Jersey × Holstein-Friesian, and Norwegian Red × (Jersey × Holstein-Friesian) cows on dry matter intake and production efficiencies in pasture-based systems
McClearn et al., 2022

Answer 174

Both cow genotype and parity affected dry matter intake, milk production, and production efficiencies of grazing dairy cows.
 Dry matter intake was:
 HF - 17.2 kg/cow/day
 Jersey x HF = , 17.0 kg/cow/day
 Norwegian red x (Jersey x HF) = 16.7 kg/cow/day

Question 175

Meta-analysis of rumination behaviour and its relationship with milk and milk fat production, rumen pH, and total-tract digestibility in lactating dairy cows
Souza et al., 2022

Answer 175

 There was little difference in average rumination time among all systems.
 The total time spent ruminating averaged 444 min/d and occurred in 13.8 bouts/d that averaged 32.7 min.
 Rumination time was quadratically increased with increasing milk fat yield (partial R2 = 0.27) and milk fat percent
 Rumination was also increased with increasing milk yield, dry matter intake, and rumen pH, and was quadratically related to dietary neutral detergent fiber (NDF) and total-tract NDF digestibility

Question 176

Plasma progesterone concentration after first service is associated with individual genetic traits, postpartum phenotypes, and likelihood of conception in seasonal-calving pasture-based dairy cows.
Rojas Canadas et al., 2021

Answer 176

Plasma progesterone concentrations after first artificial insemination were greater in lactating dairy cows that were
 (1) selected for improved genetic merit for fertility and milk production traits;
 (2) had prompt resumption of postpartum ovarian cyclicity;
 (3) had faster resolution of postpartum uterine disease; and
 (4) had better indicators of bioenergetic status during early lactation and at artificial insemination.
 Moreover, greater plasma progesterone concentrations were associated with greater pregnancy success

Question 177

Comparison of reproductive management programs for submission of Holstein heifers for first insemination with conventional or sexed semen based on expression of oestrus, pregnancy outcomes, and cost per pregnancy
Lauber et al., 2021

Answer 177

 Delaying controlled internal drug release (CIDR) removal by 24 h within a 5-d progesterone releasing intravaginal device (PRID)-Synch or a 5-d CIDR-Synch protocol suppressed early expression of ooestrus before timed artificial insemination (AI) but decreased pregnancies per AI for heifers inseminated with sexed but not conventional semen.
 Further, submission of heifers to a 5-d CIDR-Synch protocol for first AI tended to increase pregnancies per AI and decrease the cost per pregnancy compared with heifers submitted for first AI based on once-daily detection of ooestrus after treatment with prostaglandin F2α

Question 178

Integration of statistical inferences and machine learning algorithms for prediction of metritis cure in dairy cows
Oliveira et al., 2021

Answer 178

 Cows that developed metritis at >7 DIM had 2.09 higher odds of being cured than cows that developed metritis at ≤7 DIM.
 For rectal temperature, each degree Celsius above 39.4°C led to lower odds to be cured than cows with rectal temperature ≤39.4°C.
 Cows that had reduced milk production from the day before to the metritis diagnosis had lower odds to be cured than cows with moderate milk production increase
 Cows developing metritis at >7 DIM, with increase in milk production, and with a rectal temperature ≤39.40°C had increased likelihood of cure of metritis with an accuracy of 75%

Question 179

Pain in the weeks following surgical and rubber ring castration in dairy calves
Nogues et al., 2021

Answer 179

 Surgical wounds were fully healed on average 4 wk after the procedure, but only 1 calf in the rubber ring treatment fully healed within the 8-wk study
 Inflammation was greater after rubber ring castration, rubber ring castration associated with less ADG due to, in part, lower starter intake
 Calves in the rubber ring treatment spent less time lying down and licked their lesions more frequently.

Question 180

Risk factors for purulent vaginal discharge and its association with reproductive performance of lactating Jersey cows
Moraes et al., 2021

Answer 180

 The major risk factors for PVD were calving-related problems, retained fetal membrane, metritis, and days in the close-up diet.
 Pregnancy per artificial insemination following the first and second services was reduced in cows diagnosed with PVD compared with cows without PVD.
 PVD was associated with increased odds of pregnancy loss after the first service and reduced hazard of pregnancy by 305 d in milk.
 Severity of PVD was associated with odds of reproductive success

Question 181

Characterization of ketolactia in dairy cows during early lactation
Kowalski et al., 2021

Answer 181

 Fourier transform infrared spectroscopy (FTIR) allows for the determination of milk acetone (mACE) and β-hydroxybutyrate (mBHB) concentrations, providing a potential herd monitoring tool for hyperketolactia
 Published hyperketolactic threshold concentrations were used to classify study milk samples into ketolactia groups
 mACE (≥0.15 mmol/L), mBHB (≥0.10 mmol/L)
 “Normal” (mACE <0.15 mmol/L and mBHB <0.10 mmol/L)
 “hyperketolactic” (HYKL; either mACE ≥0.15 mmol/L or mBHB ≥0.10 mmol/L).
 mACE and mBHB concentrations were influenced by effects of parity, DIM, and their interaction
 Among HYKL samples, mACE was elevated soon after calving and declined over time.
 In contrast, mBHB started lower after calving and increased reaching peak concentrations around 30 DIM, and then decreased

Question 182

Effect of body condition change and health status during early lactation on performance and survival of Holstein cows
Manriquez et al., 2021

Answer 182

 BCS performed at 5DIM and 40DIM and BCS loss categorized as:
 Excessive = ΔBCS ≤−0.75
 Moderate = ΔBCS = −0.5 to −0.25
 No change = ΔBCS = 0
 BCS gain = ΔBCS ≥0.25
 Both severe loss of body condition and disease occurrences measured within 40 days in milk affected subsequent cow performance and survival.
 Odds of resumption of ovarian cyclicity lower in cows with excessive BCS loss
 Odds of pregnancy greater in cows with BCS gain vs those with excessive loss
 Cows with any disease had lower odds of resumption of ovarian cyclicity
 Reproductive disease associated with lower odds of pregnancy at 150 and 305DIM
 MY higher in cows with greater BCS loss

Question 183

Administration of internal teat sealant in primigravid dairy heifers at different times of gestation to prevent intramammary infections at calving
Larsen et al., 2021

Answer 183

 ITS administration reduced the likelihood of IMI at calving for all pathogens
 Odds of IMI at calving was similar between ITS75 and ITS35 quarters for both NAS and other pathogens
 ITS administration at either 75 and 35 d prepartum reduced IMI prevalence at calving in primigravid dairy heifers.

Question 184

Nutrient digetibility and production responses of lactating dairy cows when saturated free fatty acid supplements are included in diets: A meta-analysis
Santos Neto et al., 2021

Answer 184

 Lactating dairy cows responded better to fatty acid supplements enriched in C16:0 (Palmitic) compared with those containing C16:0 and C18:0 (Oleic).
 Supplementation increased yields of milk and milk fat but had no impact on milk protein

Question 185

Prepartum level of dietary cation-anion difference fed to nulliparous cows: Acid-base balance, mineral metabolism, and health responses
Zimpel et al., 2021

Answer 185

 Cows received prepartum diets containing +200, −50, or −150 mEq/kg of dry matter.
 Reducing the DCAD induced a compensated metabolic acidosis that increased apparent absorption of Ca and Mg and concentrations of ionized Ca in blood prepartum and on the day of calving and those of Mg postpartum
 Reducing the DCAD had effects on reducing morbidity
 Treatment did not affect the incidence or prevalence of subclinical hypocalcemia, hepatic composition, or the prevalence of fatty liver.
 Reducing the DCAD had a quadratic effect on incidence of fever, uterine diseases and morbidity.

Question 186

Reducing metabolizable protein supply: Effects on milk production, blood metabolites, and health in early-lactation dairy cows
Zang et al., 2021

Answer 186

 Three experimental diets fed from wk1-wk3 then wk4-wk13 of lactation:
 114g MP/kg DM then 107 MP/kg DM
 107 MP/kg DM then 101 MP/kg DM
 101 MP/kg DM and 101 MP/kg DM
 Milk nitrogen efficiency increased with the lower-protein diet;
 Dry matter intake, milk yield and composition, and incidence of diseases were not affected by metabolizable protein supply

Question 187

Economic impact of adding a second prostaglandin F2α treatment during an Ovsynch protocol using a meta-analytical assessment and a stochastic simulation model
Borchardt et al., 2021

Answer 187

 There was a clear benefit of an additional PGF2α treatment during the Ovsynch protocol on P/AI (+5.6 percentage units). Despite additional costs for hormones and labour, an additional treatment with PGF2α on d 8 was more profitable in 95% of all scenarios because of the associated increase in fertility.
 It turned out, however, that adding a second PGF2α treatment was more profitable in multiparous cows compared with primiparous cows.

Question 188

The effect of a double dose of cloprostenol sodium on luteal blood flow and pregnancy rates per artificial insemination in lactating dairy cows
Minela et al., 2021

Answer 188

A double dose (1.0 mg) of cloprostenol sodium may be a feasible alternative for fertility programs based on nondifferent outcomes to the two/24 treatment, lower pregnancy losses, and reduced luteal blood flow disappearance following treatment in third-plus parity cows in comparison with the single treatment.

Question 189

Behavioural changes in dairy cows with metritis in seasonal calving pasture-based dairy system
Held-Montaldo et al., 2021

Answer 189

 Lying and rumination behaviour changed in cows diagnosed with metritis, but the differences observed depended on climatic/weather variables such as rainfall during the spring and temperature-humidity index during the autumn calving season.

Question 190

Evaluation of inter-rater agreement of the clinical signs used to diagnose bovine respiratory disease in individually housed veal calves
Berman et al., 2021 (Dufur and Bucznsky)

Answer 190

 Induced cough and ear droop or head tilt assessed with a 2-scale combination of severity were the 2 BRD clinical signs whose reliability was acceptable clinically

Question 191

Assessment of the prevalence of Streptococcus uberis in dairy cow feces and implications for herd health
Sherwin et al., 2021

Answer 191

 Maintenance of S. uberis within the dairy cow environment was due to a high proportion of animals shedding S. uberis in faeces
 Detection levels were significantly higher for housed cattle compared with those at pasture.
 Increased probability of detection if cows were housed in loose straw yards, compared those in straw cubicles.
 Parity, stage of lactation, and body condition score were associated with detection.

Question 192

Association between antimicrobial use and antimicrobial resistance of Streptococcus uberis causing clinical mastitis
Martins et al., 2021

Answer 192

 The highest frequencies of resistant Strep. uberis were observed for erythromycin (80.7% resistant, R), tetracycline (R = 59%), and penicillin G (R = 57.8%),
 The overall use of antimicrobials was associated with the resistance of Strep. uberis to the antimicrobial tetracycline.

Question 193

Early prediction of respiratory disease in preweaning dairy calves using feeding and activity behaviours
Bowen et al., 2021

Answer 193

 Close monitoring of feeding and activity behaviours can allow for early detection of respiratory disease in preweaning calves.

Question 194

Association of low serum calcium concentration after calving with productive and reproductive performance in multiparous Jersey cows
Valldecabres and Silva-del-Rio et al., 2021

Answer 194

 BS for Ca taken within ~3hrs of parturition
 Ca ≤2.00 mmol/L associated with higher MY, higher SCC, reduced risk of pregnancy to first service, reduced hazard of pregnancy within 150DIM.

Question 195

Longitudinal study of Staphylococcus aureus genotypes isolated from bovine clinical mastitis
Leijon et al., 2021

Answer 195

 Staph. aureus genotype stability gives important insight about the epidemiology of intramammary infections and is useful for devising strategies for control and prevention of Staph. aureus mastitis.

Question 196

Effect of postpartum collection time and colostrum quality on passive transfer of immunity, performance, and small intestinal development in preweaning calves
Van Keulen et al., 2021

Answer 196

 Feeding high quality colostrum reduced scouring duration, enhanced surface area of duodenum and jejunum, and improved Feed Conversion Ratio during the first 5 wk of calf age.

Question 197

Effect of passive antibodies derived from rotavirus-like particles on neonatal calf diarrhoea caused by rotavirus in an oral challenge model
Bristol et al., 2021

Answer 197

 Calves fed colostrum replacer with additional antibodies had shorter duration of diarrhoeal illness compared with calves fed only milk replacer. Calves fed milk replacer with antibodies also had shorter duration of diarrhoeal illness compared with calves fed only milk replacer.

Question 198

Dairy farmer, hoof trimmer, and veterinarian perceptions of barriers and roles in lameness management
Wynands et al., 2021

Answer 198

 These findings suggest a need for increased efforts to facilitate collaboration between farmers, hoof trimmers, and veterinarians to improve lameness management on dairy farms.

Question 199

Economic impact of different strategies to use sex-sorted sperm for reproductive management in seasonal-calving, pasture-based dairy herds
Ruelle et al., 2021

Answer 199

 In almost all situations, when the relative P/AI with SS was ≥85%, use of SS led to an overall increase of the farm net profit
 If the relative P/AI with SS was <70%, the use of SS led to a decrease in profitability in all simulations except for when cows were AI’ed to FTAI.

Question 200

Growth, milk production, reproductive performance, and stayability of dairy heifers born from 2-year-old or mixed-age dams
Handcock et al., 2021

Answer 200

 Based on the results of this study, there were no disadvantages to keeping replacement heifers from first-calving dams.
 The progeny of dams ≥9 yr old had the lowest milk solids production in first (297.8 ± 1.6 kg), second (341.6 ± 1.8 kg), and third lactations (393.2 ± 2.4 kg).
 Keeping replacements from dams aged 9 yr and over could not be recommended.

Question 201

Prepartum level of dietary cation-anion difference fed to nulliparous cows: Lactation and reproductive responses
Zimpel et al., 2021

Answer 201

 Reducing DCAD depressed intake prepartum but had no effect on colostrum yield or composition or postpartum productive performance.
 Reducing DCAD increased the proportion of pregnant cows by 305 d postpartum but had no effect on the rate of pregnancy.
 Manipulating the DCAD of prepartum diets fed to nulliparous cows did not benefit postpartum production but had some benefit to reproduction.

Question 202

Method of diet delivery to dairy cows: Effects on nutrient digestion, rumen fermentation, methane emissions from enteric fermentation and stored manure, nitrogen excretion, and milk production
Benchaar and Hassanat, 2021

Answer 202

 Method of diet delivery had no effect on DM intake, but neutral detergent fiber (NDF) intake was greater when the diet was delivered as TMR as compared with CF
 Daily duration of ruminal pH <5.6 was less when the diet was delivered as TMR and this was associated with an improved NDF digestibility

Question 203

Effects of dietary phosphorus concentration during the transition period on plasma calcium concentrations, feed intake, and milk production in dairy cows
Keanthao et al., 2021

Answer 203

 The feeding of diets containing 2.2 g of P/kg of DM during the last 6 wk of the dry period and 2.9 g of P/kg of DM during early lactation increased plasma Ca levels when compared with greater dietary P levels. These low-P diets may be instrumental in preventing hypocalcemia in periparturient cows and do not compromise DM intake and milk production.

Question 204

Determination of energy and protein requirements of preweaned dairy calves: A multistudy approach
Marcondes and Silva, 2021

Answer 204

 The NEM was estimated as 70.2 kcal/metabolic body weight per day.
 The efficiencies of use of metabolizable energy and protein are greater for milk when compared with milk replacer and starter feed.

Question 205

Daily activity measures and milk yield immediately before and after a fertile oestrus and during the period of expected return to oestrus after insemination in dairy cows
Stevenson et al., 2021

Answer 205

 Resting and rumination activity decreased to daily nadirs, whereas eating and high activity peaked at ooestrus.
 Cows that returned to ooestrus after insemination had greater daily eating and high activity times and lower rumination and resting times during the expected time of ooestrus on d 21 through 26 after insemination compared with pregnant cows and cows failing to return to ooestrus.

Question 206

Comprehensive functional analysis reveals that acrosome integrity and viability are key variables distinguishing artificial insemination bulls of varying fertility
Bernecic et al., 2021

Answer 206

 Spermatozoa were assessed for motility and kinematic parameters, morphology, acrosome integrity, plasma membrane lipid packing, viability (or membrane integrity), superoxide production, and DNA integrity
 Acrosome integrity and viability were the only sperm attributes that were significantly different between high- and low-fertility bulls
 Viability and acrosome integrity could serve as fertility biomarkers in the field and, when used alongside other sperm attributes, may be useful in detecting low-fertility bulls.

Question 207

Effects of feeding rumen-protected methionine pre- and postpartum on reproductive outcomes of multiparous Holstein cows
Stangaferro et al., 2021

Answer 207

 Feeding rumen-protected Met did not affect pregnancy per AI or pregnancy loss measured at several time points after timed AI and did not affect other secondary outcomes, including uterine health, ovarian cyclicity, response to synchronization of ovulation, or embryo development and survival.

Question 208

Effects of delaying increase in milk allowance and type of gradual weaning program on performance and health of calves fed lower levels of milk
Parsons et al., 2021

Answer 208

 Calves randomly assigned to 1 of 2 milk level treatments and 1 of 2 weaning treatments:
 From d13 calves either fed 5L/d milk or an increasing plane to 9L/d
 2-step weaning program or 4-step weaning program from d30-45.
 Calves fed less milk consumed more starter during the preweaning and weaning periods, but a similar amount postweaning.

Question 209

Diagnosis of respiratory disease in preweaned dairy calves using sequential thoracic ultrasonography and clinical respiratory scoring: Temporal transitions and association with growth rates
Rhodes et al., 2021(Mee, Pardon McAloon)

Answer 209

 TUS and CRS scores were weakly correlated. The TUS was associated with reduced ADG.
 Calves with TUS scores ≥3 grew at 126 g/d less than unaffected calves over the 3-wk period before examination.
 The predicted effect on ADG was dependent on the age and duration over which the animal was affected
 There was no association of Clinical Respiratory Scoring with ADG.
 Weight gain was lowest in animals with consistently high TUS scores (i.e. in chronic cases)

Question 210

Effects of feeding level, milking frequency, and single injection of cabergoline on feed intake, milk yield, milk leakage, and clinical udder characteristics during dry-off in dairy cows
Larsen et al., 2021

Answer 210

 Reduced feeding level induced negative energy balance, which may compromise welfare due to metabolic stress and hunger
 No clear differences in risk of milk leakage after dry-off were observed between abrupt and gradual dry-off management strategies.
 Use of cabergoline led to fewer signs of milk leakage and reduced udder engorgement during the first days after dry-off, which may positively affect welfare at dry-off

Question 211

Animal welfare outcomes and associated risk indicators on Austrian dairy farms: A cross-sectional study
Schenkenfelder and Winckler, 2021

Answer 211

 We found frequent associations with welfare outcome measures for the amount of milk delivered per cow (e.g., lower risk of very lean cows or dirty hind legs but higher risk of mastitis treatments or antibiotic dry-off with increasing milk delivery), housing system (e.g., loose-housed animals were at lower risk of lesions on the tarsal joint than animals kept in tiestalls, but at higher risk of being classified as very fat),
 Beneficial associations were consistently found for an increasing number of days with access to pasture (e.g., body condition, integument alterations, lameness) as well as organic compared with conventional farming

Question 212

Effect of timing of prepartum vaccination relative to pen change with an acidogenic diet on lying time and metabolic profile in Holstein dairy cows and serum and colostrum immunoglobulins in Holstein dairy cows
Menichetti et al., 2021

Answer 212

 The shorter the interval between administration of prepartum booster vaccination and calving, the lower the colostral IgG concentrations.
 Vaccinating cows at 28 d prepartum, 7 d before pen change with an acidogenic diet, improved colostral IgG concentrations at calving and tended to reduce the rate of clinical mastitis within the first 150 DIM compared with cows immunized concurrent with a pen change at 21 d prepartum

Question 213

Evaluation of 4 predictive algorithms for intramammary infection status in late-lactation cows
Rowe et al., 2021

Answer 213

 We recommend that producers implementing algorithm-guided SDCT use algorithm criteria that matches their relative aspirations:
 For reducing antibiotic use (high specificity, positive predictive value)
 For minimizing untreated IMI at dry-off (high sensitivity, negative predictive value).

Question 214

Standing behaviour and sole horn lesions: A prospective observational longitudinal study

Eriksson et al., 2021

Answer 214

 Cows that spend more time standing and engage in longer standing bouts in the weeks after calving were at increased risk of developing sole haemorrhages and sole ulcers later in lactation.

Question 215

Detecting and predicting changes in milk homogeneity using data from automatic milking systems
Anglart et al., 2021

Answer 215

 Using data from AMS to detect and predict changes in milk homogeneity seems to be possible, although the prediction performance for the definitions of clots used in this study was poor.

Question 216

Changes in social and feeding behaviours, activity, and salivary serum amyloid A in cows with subclinical mastitis
Caplen and Held, 2021

Answer 216

 An increase in salivary SAA occurs during subclinical mastitis; SAA was higher in SCM cows and demonstrated a positive (weak) correlation with SCC
 Cows with subclinical mastitis demonstrated changes in activity:
 Distance moved, social exploration, social reactivity (here: likelihood to be displaced following receipt of agonism), performance of social grooming and head butts, and the receipt of agonistic noncontact challenges
 Cows with subclinical mastitis demonstrated altered feeding patterns:
 Spent a greater proportion of feeding time in direct contact with 2 conspecifics, and a lower proportion of feeding time at self-locking feed barriers

Question 217

Evaluation of bull fertility in Italian Brown Swiss dairy cattle using cow field data
Pacheco et al., 2021

Answer 217

 There is a substantial variation in conception rate among Brown Swiss bulls, with more than 20% conception rate difference between high-fertility and low-fertility bulls.

Question 218

The effects of organic grass and grass-birdsfoot trefoil pastures on Jersey heifer development:
Heifer growth, performance, and economic impact.
Herbage characteristics affecting intake
Hadfield et al., 2021

Answer 218

 The addition of BFT to organic pasture improves growth of grazing replacement heifers.
 Heifer hip height and fecal egg counts were not affected by treatment.

Question 219

Effect of dietary supplementation of 2 forms of a B vitamin and choline blend on the performance of Holstein calves during the transition and postweaning phase
Molano et al., 2021

Answer 219

 Additional B vitamins and choline did not improve calf performance before, during, or after weaning.

Question 220

Dietary protein oscillation: Effects on feed intake, lactation performance, and milk nitrogen efficiency in lactating dairy cows
Rauch et al., 2021

Answer 220

 Oscillating (OS) dietary crude protein (CP) concentration may improve nitrogen use efficiency (NUE)
 Overall, performance and NUE were unaffected by OS treatment, but apparent total-tract digestibility and milk urea concentration increased:
 No difference in DMI, MY, milk component yields did not vary between groups
 Milk urea concentration was higher, dry matter digestibility, NDF digestibility was higher for OS compared with ST

Question 221

Effects of 2 liquid feeding rates over the first 3 months of life on whole-body energy metabolism and energy use efficiency of dairy calves up to 5 months

Answer 221

 Either:
 Colostrum 10%BR then MR 10%BW
 Colostrum 12%BR then MR 20%BW
 20%-MR calves showed greater efficiency estimates preweaning, but this effect did not occur after weaning, suggesting that energy use efficiency does not persist until later stages in life.

Question 222

Effect of monensin on milk fatty acid profile in dairy cows and on the use of fatty acids for early diagnosis of elevated blood plasma concentrations of nonesterified fatty acids and hyperketonemia
Henno et al., 2021

Answer 222

 Precalving continuous-release monensin capsule administration affected postcalving milk fatty acid profile and the identification accuracy of most estimated FA for NEFA cows and some FA for HYK cows.
 Specific milk fatty acid thresholds for identification of NEFA and HYK cows are applicable only within similar feeding conditions and rumen environment.

Question 223

Effect of treatment of pneumonia and otitis media with tildipirosin or florfenicol + flunixin meglumine on health and upper respiratory tract microbiota of preweaned Holstein dairy heifers
Bringhenti et al., 2021

Answer 223

 No differences were found in number of treatments or recurrence risk of pneumonia or otitis
 Both drugs used in the study were effective in reducing rectal temperature, ear scores, leukocyte counts, and mean relative abundance of the genera Mannheimia, Pasteurella, and Moraxella in the URT.
 Neither were effective at reducing the mean relative abundance of Mycoplasma

Question 224

The effect of pair housing on dairy calf health, performance, and behaviour
Buckova et al., 2021

Answer 224

 There were no effects of housing on calf health, feed intake, or average daily gain.

Question 225

Antimicrobial resistance and virulence characteristics in 3 collections of staphylococci from bovine milk samples
Fergestad et al., 2021

Answer 225

 Antimicrobial resistance was common in Staphylococcus epidermidis and Staphylococcus haemolyticus from all different groups, with resistance to trimethoprim-sulfonamide frequently occurring in Staph. epidermidis and Staph. haemolyticus as well as in Staph. aureus.

Question 226

Detecting intramammary infection at the end of lactation in dairy cows
McDougall et al., 2021

Answer 226

 The average, maximum, and last cow-composite SCC of lactation were all predictive of presence of a major pathogen IMI and did not differ in their ability to discriminate infected from uninfected cows.
 Optimal cut points for:
* Last SCC: 108 × 1,000 cells/mL
* Maximum SCC: 152 × 1,000 cells/mL
* Average SCC: 105 × 1,000 cells/mL
 Cow-composite SCC on its own resulted in sensitivities and specificities of between 0.76 and 0.86, and 0.71 to 0.80, respectively, for determination of presence of major pattern IMI, and the predictive value was not improved by addition of other predictor variables.

Question 227

The effect of new bovine viral diarrhoea virus introduction on somatic cell count, calving interval, culling, and calf mortality of dairy herds in the Dutch bovine viral diarrhoea virus–free program
Yue et al., 2021

Answer 227

 Free herds have lower SCC, culling risk, calf mortality rate, and shorter calving interval than the breakdown herds.
 New BVDV introduction affected the SCC and CMR.
 A new introduction of BVDV had a negative but on average relatively small effect on herd performance in herds participating in a BVDV control program.

Question 228

Assessing effects of dietary and milking frequency changes and injection of cabergoline during dry-off on hunger in dairy cows using 2 feed-thwarting tests
Franchi et al., 2021

Answer 228

 Reducing feeding level, either before or on the dry-off day, resulted in consistently increased feeding motivation, interpreted as a sign of hunger.
 No clear effects of change in milking frequency, singly or combined with reduced diet energy density, on feeding motivation were found.
 The effects of cabergoline on feeding motivation are not easily interpreted and warrant further investigation.

Question 229

A study on the use of thermal imaging as a diagnostic tool for the detection of digital dermatitis in dairy cattle
Anagnostopoulos et al., 2021

Answer 229

 All clinical stages of digital dermatitis were associated with increased foot skin temperature.
 Feet with active lesions were recorded having higher mean interdigital skin temperature compared with feet with chronic, inactive digital dermatitis lesions and nonaffected feet.
 IST was highest in feet with M2 lesions, followed by M1 and M4.1 lesions.
 This method can be used precalving with a sensitivity of 0.88, and a specificity of 0.66

Question 230

Associations between feeding behaviours collected from an automated milk feeder and disease in group-housed dairy calves in Ontario: A cross-sectional study
Conboy et al., 2021

Answer 230

 Total milk consumption, the percentage of milk allotment consumed, drinking speed, and the number of unrewarded visits were all significantly associated with 2 or more of bovine respiratory disease, neonatal calf diarrhoea, or general disease.

 The sensitivity of disease detection was low; thus, to increase it, parallel interpretation was completed. With parallel interpretation, the use of an automated milk feeder can be a useful preliminary tool in disease detection.
 Parallel testing resulted in a sensitivity of 0.82, 0.78, and 0.84, and a specificity of 0.26, 0.23, and 0.21, for BRD, NCD, and general disease, respectively. This suggests that automated milk feeders may serve as a useful preliminary tool in the detection of diseased calves.

Question 231

Associations between the metabolic status of the cow and colostrum quality as determined by Brix refractometry
Immler et al., 2021

Answer 231

 Cows entering second parity had lower Brix values compared with cows entering third or greater parity
 Prepartum vaccination of cows led to higher Brix values compared with nonvaccinated cows.
 Cows with a moderate to high lameness score had lower Brix values than cows with low-grade lameness.
 An increase of glutamate dehydrogenase serum activity and serum calcium concentration were associated with lower Brix values
 An increase in the difference of total protein and albumin serum concentration led to higher Brix values

Question 232

Homogeneity density scores of quarter milk in automatic milking systems
Sandgren et al., 2021

Answer 232

 Clot density was scored based on coverage of the filter area as 0 (negative), 1 (trace), 2 (mild), 3 (moderate), 4 (heavy), and 5 (very heavy).
 Quarter Milking Sample 3 could be a reasonable threshold for detecting quarters with abnormal milk that require further attention.

Question 233

Evaluation of test characteristics of 2 ELISA tests applied to bulk tank milk and claw-trimming records for herd-level diagnosis of bovine digital dermatitis using latent class analysis
Holmoy et al., 2021

Answer 233

 Neither of the 2 ELISA tests yielded satisfactory sensitivity without compromising specificity.
 For Medicago’s ELISA test, an Se (95% posterior credible interval) of 0.57 (0.32; 0.94) could be achieved without compromising Sp
 For GD Animal Health’s in-house ELISA test, an Se of 0.60 (0.37; 0.92) was achieved without compromising Sp.
 Currently, inspection at trimming in a chute is necessary for surveillance of digital dermatitis in Norway, although these ELISA tests of bulk tank milk might be a useful supplement.

Question 234

The effect of pegbovigrastim on early-lactation disease, production, and reproduction in dairy cows
Schyndel et al., 2021

Answer 234

 Cows that received pegbovigrastim produced approximately 1 kg/d less milk in early lactation

Question 235

Effects of early social contact on dairy calf response to initial social grouping and regrouping
Lindner et al., 2021

Answer 235

Housing treatment did not affect calf health, performance, ability to learn to use the teat in the first 2 wk, or use of an autofeeder after grouping.
 Following initial grouping and regrouping, previously pair-housed calves spent more time lying socially, but previous social contact did not affect interaction with novel pen resources or locomotor activities.

Question 236

Effects of prepartum dietary protein level and feed intake on postpartum lactation performance and feeding behaviour of multiparous Holstein dairy cows
Akhtar et al., 2021

Answer 236

 Feeding a prepartum high-protein diet combined with restricted intake can provide benefits of both strategies than relying independently on increased dietary protein or restricted intake.

Question 237

Effects of mixed tocopherols added to milk replacer and calf starter on intake, growth, and indices of stress
Quigley et al., 2021

Answer 237

 Holstein calves fed MR and starter supplemented with 0, 5, 10, or 15 mg/kg of BW mixed tocopherols daily from 2-3d until 56d of age.
 Data suggests that tocopherols may improve an animal’s oxidative status, directing more nutrients toward growth and improving animal efficiency. Further consideration should be given to the effects of these isoforms in diets of ruminants

Question 238

Effects of rumen-protected choline supplementation in Holstein dairy cows during electric heat blanket-induced heat stress
Holdorf et al., 2021

Answer 238

 RPC tended to reduce the increase in RR, increased MY, reduced fatty acid and tryglyceride concentrations and increased revised insulin sensitivity.
 Rumen-protected choline partially mitigated the effect of heat stress in mid-lactation cows

Question 239

Effect of a calcium-energy supplement drink at calving on lactation performance: Milk yield and composition, odds to reach a next lactation, and calving interval
Daniel et al., 2021

Answer 239

 81% cows voluntarily consumed the Ca supplement
 No MY or composition differences for multiparous cows
 Primiparous cows had increased MY and composition, decreased risk of subclinical ketosis, and increased calving interval.

Question 240

Prevalence of digital dermatitis using mirror scoring in Finnish freestall dairy herds
Pirkkalainen et al., 2021

Answer 240

 Mirror scoring in a milking parlor or a pen without washing the feet was an easy way to score cows for digital dermatitis, but its sensitivity was relatively low, especially for active lesions. However, this method would be suitable for longitudinal monitoring and control of digital dermatitis within farms.

Question 241

Antimicrobial susceptibilities in dairy herds that differ in dry cow therapy usage
McDougall et al., 2021

Answer 241

 Generally, the MIC of CNS and streptococcal isolates from organic herds were lower than isolates from herds using DCT. However, the differences in MIC distributions occurred at MIC below clinical breakpoints, so that the bacteriological cure rates may not differ

Question 242

Evaluation of chromogenic culture media for rapid identification of microorganisms isolated from cows with clinical and subclinical mastitis
Granja et al., 2021

Answer 242

 2 experiments performed to evaluate biplate and triplate chromogenic culture media, c.f. MALDI-TOF.
 Biplate – G+ve versus G-ve
 Triplate - Streptococcus and Strep-like organisms, Staphylococcus, and gram-negative bacteria.
 For CM and SCM, accuracy of the methods varied by causative pathogen
 The results of chromogenic culture media may be useful for rapid decision-making on mastitis treatment protocols of the main mastitis-causing microorganisms, but their use for implementation of mastitis control measures will depend on each farm specific needs.

Question 243

Association of days in close up, gestation length, and rumination around time of calving with disease and pregnancy outcomes in multiparous dairy cows
Cook et al., 2021 (Viora author)

Answer 243

 We did not find any significant association between precalving rumination time and disease within the first 30 DIM.
 Higher rumination time in the week before calving was shown to be strongly linked to a shorter time to subsequent pregnancy, whereas rumination times postcalving were not associated with changes in the time to pregnancy.
 A curvilinear combination of gestation length and duration in the close-up pen was significantly associated with changes in disease incidence in the first 30 DIM

Question 244

Increased teat wall thickness in response to machine milking
Stauffer et al., 2021

Answer 244

 The increase in size of thick-walled veins in the teat tissue is the main reason for the thickening of the teat walls in response to machine milking.

Question 245

Randomized controlled field trial comparing quarter and cow level selective dry cow treatment using the California Mastitis Test
Swinkels et al., 2021(Green and Bradley author)

Answer 245

 Cows categorized as “high” (any of the last 3 monthly individual SCC ≥200,000cells/mL or an occurrence of CM within that period) or “low” SCC and assigned to three treatment groups:
 Antibiotic treatment administered at the cow level
 Antibiotic treatment administered at the quarter level if CMT score 2
 Antibiotic treatment administered at the quarter level if CMT score 3
 Leaving quarters untreated with intramammary antibiotic in cows in the high cell count group, with a CMT <2 or <1, reduced antibiotic use by 55% and 31%, respectively, and resulted in no difference in the odds of being infected with any pathogen postcalving, but was associated with a higher SCC at the first test day.
 No differences in clinical mastitis incidence and milk yield in the first 100 d in milk were detected between any of the treatment groups.
 These study findings support selective quarter level dry off treatment only in cows with cow level SCC >200,000 cells/mL at dry off.

Question 246

Associations between dry period length and time to culling and pregnancy in the subsequent lactation
Pattamanont et al., 2021

Answer 246

 Compared to a dry period length of 51-60d
 Dry period lengths shorter or longer than the conventional length of approximately 55 d were associated with slightly greater risks of culling

Question 247

Effect of β-carotene supplementation to prepartum Holstein cows on colostrum quality and calf performance
Aragona et al., 2021

Answer 247

 β-carotene supplementation did not affect colostrum quality or yield but increased the solids content of colostrum. Calves fed colostrum from cows supplemented with β-carotene had decreased apparent efficiency of absorption of immunoglobulin G but improved feed efficiency.

Question 248

Effects of protein content and rumen-undegradable to rumen-degradable protein ratio in finely ground calf starters on growth performance, ruminal and blood parameters, and urinary purine derivatives
Yousefinejad et al., 2021

Answer 248

 Growth performance was positively influenced by greater starter protein content because of increased microbial protein synthesis and blood insulin concentration.

Question 249

Effects of maternal level of dietary cation-anion difference fed to prepartum nulliparous cows on offspring acid-base balance, metabolism, and growth
Zimpel et al., 2021

Answer 249

Males were born heavier than females, but maternal DCAD did not affect birth weight of all calves (P200 = 37.7 vs. N50 = 37.3 vs. N150 = 37.8 ± 0.7 kg) or daily weight gain in females in the first 56 d of life (P200 = 0.80 vs. N50 = 0.81 vs. N150 = 0.77 ± 0.03 kg/d). Treatment did not affect intake of milk (P200 = 1.11 vs. N50 = 1.04 vs. N150 = 1.19 ± 0.06 kg/d) or starter grain DM (P200 = 0.27 vs. N50 = 0.27 vs. N150 = 0.21 ± 0.06 kg/d), or measures of feed efficiency. Treatment did not affect concentrations of minerals in serum, morbidity, or age at morbidity. Manipulating the DCAD of pregnant nulliparous dams during late gestation did not affect offspring performance in the first 2 mo of age.

Question 250

Effects of calfhood respiratory disease on health and performance of dairy cattle: A systematic review and meta-analysis
Buczinski et al., 2021

Answer 250

 Heifers diagnosed with calfhood BRD (up to 12months of age) had higher odds of dying and of herd removal before first calving compared with heifers never diagnosed with this condition.
 Heifers with calfhood BRD also had a decreased average daily gain and produced less milk during their first lactation.

Question 251

The effect of neomycin inclusion in milk replacer on the health, growth, and performance of male Holstein calves during preweaning
Buss et al., 2021

Answer 251

 Growth performance, feed intake, and feed conversion ratio were not different.
 The current study provides evidence that neomycin inclusion in milk replacer reduces fecal scores and the duration of diarrhoea in calves but does not improve other indicators of health or growth performance.

Question 252

Effects of extended voluntary waiting period from calving until first insemination on body condition, milk yield, and lactation persistency
Burgers et al., 2021

Answer 252

 The waiting period could be extended until 200 d for primiparous cows and until 125 d for multiparous cows without an effect on milk yield per day of calving interval.
 The VWP could be extended from 50 d to 125 d without an effect on daily yield per day of calving interval.
 Extending VWP until 200 d for primiparous cows did not affect their daily milk yield, but multiparous cows with a 200-d VWP had a reduced milk yield per day of calving interval and an increased body condition in late lactation and the subsequent lactation, compared with multiparous cows with a 50-d VWP.

Question 253

The hidden cost of disease:
I. Impact of the first incidence of mastitis on production and economic indicators of primiparous dairy cows

Puerto et al., 2021

Answer 253

 Significant losses in cumulative milk yield (−382 to −989 kg) and correspondingly lower fat and protein yields were found in mastitic cows, with transition and late-lactation mastitic cows having the highest losses
 cows that had a first instance of mastitis at any of the 4 lactation stages had lower milk production than healthy cows
* Transition: MY reduction of 8%
* Early lactation: MY reduction of 6%
* Mid lactation: MY reduction of 5%
* Late lactation: MY reduction of 10%

Question 254

Impact of the first incidence of lameness on production and economic indicators of primiparous dairy cows

Puerto et al., 2021

Answer 254

 Cows experiencing an instance of lameness in any of the 4 investigated lactation stages experienced significant reductions in cumulative milk yield and milk components.
 The largest reductions in milk yield were in transition lame cows, at 1,200 kg less over the course of their lactation compared with healthy cows

Question 255

Estimating milk loss based on somatic cell count at the cow and herd level
Chen et al., 2021

Answer 255

 The traditional approach of using bulk tank somatic cell count (SCC) to estimate total herd milk loss due to subclinical SCC inaccurately assesses reductions in milk loss.
 Estimates of total herd milk yield loss vary with the distribution of cow-level SCC and parity within the herd, so it is imperative that milk loss be calculated on a per cow basis and summed to calculate the total herd loss

Question 256

Models to predict the risk of subacute ruminal acidosis in dairy cows based on dietary and cow factors: A meta-analysis
Khorrami et al., 2021

Answer 256

 As a rule of thumb, when taken separately, we propose 15 to 18% peNDF >8 as a safe range for diet formulation to prevent SARA, when starch or NFC levels are within 20 to 25% and 35 to 40% ranges, respectively.
 At dietary starch content below 20% of DM, grain type was insignificant in affecting ruminal pH.
 Given that a lower ruminal pH is expected in these high-risk cows, it is advisable to keep the lower end of recommended starch (20%) and higher peNDF >8 (18%) contents in the diet of these cows.

Question 257

Effects of feeding milk replacer at a moderate rate, ad libitum, or with a step-up program on Holstein calf growth performance to 4 months of age
Suarez-Mena et al., 2021

Answer 257

 Feed efficiency was lower when MR was fed ad libitum, and growth advantages observed at 2 mo were lost by 4 mo of age

Question 258

Sire contribution to fertilization failure and early embryo survival in cattle
O’Callaghan et al., 2021

Answer 258

 Using Holstein Friesian bulls exhibiting extremes in fertility typical of those in artificial insemination, we report that although differences in field fertility were not reflected in fertilization rate, differences in embryo quality were apparent as early as d 7.
 These differences were reflected in a higher proportion of conceptuses surviving to d 15 in high-fertility bulls, which coincides with the period of maternal recognition of pregnancy in cattle.

Question 259

Relationships between energy balance during early lactation and cow performance, blood metabolites, and fertility: A meta-analysis of individual cow data
Civiero et al., 2021

Answer 259

 Cows with improved energy balance in early lactation had a shorter interval to start of luteal activity, greater milk progesterone concentrations at start of luteal activity, and earlier first observed heats.
 Early-lactation energy balance did not affect conception rate to first service

Question 260

Effect of enhanced hygiene on transmission of Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae in dairy herds with automatic milking systems
Skarbye et al., 2021

Answer 260

 An automatic spray on the upper surface of the brush motor with disinfectant along with daily change of brushes collectively reduced transmission of Strep. agalactiae and Strep. dysgalactiae

Question 261

Predicting morbidity and mortality using automated milk feeders: A scoping review
Morrison et al., 2021

Answer 261

 Daily milk consumption, drinking speed, and rewarded and unrewarded visits may provide insight into early disease detection in preweaned dairy calves

Question 262

Nutraceutical intervention with colostrum replacer: Can we reduce disease hazard, ameliorate disease severity, and improve performance in preweaned dairy calves?
Cantor et al., 2021

Answer 262

 Calves fed a preventative dose of colostrum replacer, versus a placebo, were less likely to develop pneumonia 14 d later, but this treatment did not affect growth.
 No difference was found for risk of diarrhoea
 CR may reduce BRD likelihood but did not influence growth in calves offered high allowances of milk

Question 263

Associations between days on close-up diets and immune responses prepartum, metabolites peripartum, and risk of postpartum diseases in Jersey cows
Chebel et al., 2021

Answer 263

 Quadratic associations between days on the close-up diet and the risk of uterine diseases and energy-corrected milk yield were detected, with 28 d on the close-up diet resulting in lowest incidence of disease and greatest milk yield.

Question 264

The effect of stocking density and a blind on the behaviour of Holstein dairy cattle in group maternity pens.
Part I: Calving location, locomotion, and separation behaviour
Part II: Labor length, lying behaviour, and social behaviour

Creutzinger et al., 2021

Answer 264

 Increased space and a blind may allow cows to perform natural behaviours before calving.
 Presence of a blind reduced attention from other cows around calving
 Animals in pens with a blind had shorter labor lengths than those without a blind

Question 265

Scoping review on clinical definition of bovine respiratory disease complex and related clinical signs in dairy cows
Ferraro et al., 2021

Answer 265

 Based on our results, the current literature lacks a clear repeatable clinical definition of infectious respiratory disease in adult dairy cows.
 The most commonly reported clinical signs were fever (without specifying a precise temperature threshold), nasal discharge, cough, and dyspnea

Question 266

Failure of clinical cure in dairy cows treated for metritis is associated with reduced productive and reproductive performance
Figueiredo et al., 2021

Answer 266

 Cows diagnosed with metritis that do not undergo clinical cure by 10 d of onset of antimicrobial therapy have impaired reproductive performance, reduced milk production, and increased risk of leaving the herd.
o Failure of clinical cure associated with a smaller proportion of cyclic cows, reduced P/AI, greater pregnancy loss, reduced hazard of pregnancy by 300DIM and lower milk production for the first 10 months postpartum
o In comparison, metritis that cured was associated with reduced MY for 2 months PP

Question 267

A history of lameness and low body condition score is associated with reduced digital cushion volume, measured by magnetic resonance imaging, in dairy cattle
Wilson et al., 2021

Answer 267

 The volume of the digital cushion was negatively associated with the number of lameness events or CHL recorded.
 Animals with body condition score >3, culled later in lactation, or of a greater body weight were more likely to have a higher volume of digital cushion in the lateral claws.

Question 268

A history of lameness and low body condition score is associated with reduced digital cushion volume, measured by magnetic resonance imaging, in dairy cattle
Wilson et al., 2021

Answer 268

 The volume of the digital cushion was negatively associated with the number of lameness events or CHL recorded.
 Animals with body condition score >3, culled later in lactation, or of a greater body weight were more likely to have a higher volume of digital cushion in the lateral claws.

Question 269

Effect of preweaning disease on the reproductive performance and first-lactation milk production of heifers in a large dairy herd
Abuelo et al., 2021

Answer 269

 Heifers with a history of BRD before weaning were less likely to be inseminated or achieve first calving than heifers without BRD. However, BRD status did not change the age at first insemination of calving among those being inseminated or reaching first calving, respectively
 A history of diarrhoea preweaning was not associated with changes in the probability of being inseminated, having a confirmed pregnancy, or reaching first calving. However, heifers affected by diarrhoea required more inseminations to become pregnant. Diarrhoea status was also associated with a 325-kg reduction in 305ME in the first lactation and a 50 g/d reduction in ADG.

Question 270

Dry period management and new high somatic cell count during the dry period in Dutch dairy herds under selective dry cow therapy
Krattley-Roodenburg et al., 2021

Answer 270

 Variables associated with a lower proportion of new high SCC on herd level during the dry period were:
o The use of dip or spray after drying off
o A higher animal-defined daily dose of intramammary antimicrobials for DCT
o The use of DCT in low-SCC cows based on SCC or mastitis history
o Correct knowledge of DCT guidelines
o An awareness of importance of low infection rate and good hygiene during dry-off.
 Variables associated with a higher proportion of new high SCC on herd level were:
o Dry cow housing other than cubicles
o A higher animal-defined daily dose for intramammary antimicrobials for mastitis.

Question 271

Prevalence, risk factors, and effects on fertility of cytological endometritis at the time of insemination in Norwegian Red cows
Diaz-Lundahl et al., 2021

Answer 271

 The cut-off level for PMN defined as CYTO was set to 3.0%, representing the level at which the PMN occurrence affected pregnancy outcome, with the highest summation of sensitivity (32.4%) and specificity (74.9%).

Question 272

Controlled trial of the effect of negative dietary cation-anion difference prepartum diets on milk production, reproductive performance, and culling of dairy cows

Couto Serrenho et al., 2021

Answer 272

Under commercial herd conditions, prepartum negative DCAD diets improved milk production and reproductive performance, and reduced culling risk in multiparous cows. In primiparous cows, TRT diets had no effect on milk yield or culling, but increased the time to pregnancy. Our results suggest that negative DCAD diets should be targeted to multiparous cows.

Question 273

Controlled trial of the effect of negative dietary cation-anion difference on postpartum health of dairy cows

Couto Serrenho et al., 2021

Answer 273

We detected no treatment effects on RP, metritis, hyperketonemia, or PVD incidence. Cows fed TRT had lesser incidence of DA (1.7 ± 0.7% vs. 3.6 ± 1.6%) and tended to have lesser incidence of MAST compared with CON (1.8% ± 0.6% vs. 4.4 ± 1.4%). No treatment effect was detected on ≥1 disease events (TRT: 38 ± 7%, vs. CON: 42 ± 8%); however, multiparous cows on TRT were less likely to have ≥2 disease events than cows on CON (14 ± 4% vs. 23 ± 6%).

Question 274

Effects of flow-controlled vacuum on milking performance and teat condition in a rotary milking parlour

Reinemann et al., 2021

Answer 274

 Flow-controlled vacuum increased peak milk flowrate by 12% and increased average milk flowrate by 4%.

 The occurrence of rough teat ends was slightly reduced during the flow-controlled vacuum period
 The reduction in milking duration of individual cows allows a higher rotary parlor speed

Question 275

Factors associated with estrous expression and subsequent fertility in lactating dairy cows using automated activity monitoring.
Tippenhauer et al. 2021

Answer 275

 Peak activity was associated with P/AI, with 1.35 greater odds of pregnancy for cows with high PA compared with cows with low PA
 Increased THI 1 wk before AI was associated with shorter duration of ooestrus, lower peak of activity, and decreased P/AI.

Question 276

Morphology, adipocyte size, and fatty acid analysis of dairy cattle digital cushions, and the effect of body condition score and age.
Newsome et al., 2021

Answer 276

 Adipocyte size was similar across all 4 claws and across all ages
 Animals with a BCS of 3.00 or higher had a significantly increased cell size in comparison to those with a score of less than 2.50

Question 277

Pairwise comparison locomotion scoring for dairy cattle.
Gardenier et al., 2021

Answer 277

 Pairwise scoring consists of identifying the relative rank (i.e. which one is more lame) between two individuals
 Pairwise scoring and scaling had the scoring consistency of binary absolute scoring with finer continuous granularity than 4-level absolute scoring. The pairwise scoring method, and associated scaling, offer a more consistent and informative alternative to conventional absolute multilevel locomotion scoring.

Question 278

Relationship between intramammary infection and antibody concentrations in Jersey and Holstein colostrum
Enger et al., 2021

Answer 278

 Infection status at parturition does not markedly affect colostrum antibody concentrations and quality
 In Holsteins, concentrations of IgG1, IgG2, and IgA were greater in multiparous cows than primiparous cows; but this was not true for jersey cows.

Question 279

Milk- and starter-feeding strategies to reduce cross sucking in pair-housed calves in outdoor hutches.
Salter et al., 2021

Answer 279

 Cross sucking occurred for at least twice as long in pairs with buckets only
 Regardless of starter treatment, calves spent less time cross sucking when fed milk in teat buckets
 When calves are fed milk in open buckets, a novel option for reducing cross sucking is to provide starter through a specialized bottle. Nonetheless, providing milk in slow-flow teat buckets had the greatest effect on reducing cross sucking by directing suckling to the teat instead of another calf or pen objects.

Question 280

Postcalving udder health and productivity in cows approaching dry-off with intramammary infections caused by non-aureus Staphylococcus, Aerococcus, Enterococcus, Lactococcus, and Streptococcus species. Rowe et al., 2021

Answer 280

 Aseptic quarter level samples taken from cows approaching dry off and cows followed until 120DIM
 The presence of late-lactation IMI caused by major pathogens was positively associated with postcalving clinical mastitis
 IMI caused by Streptococcus and Streptococcus (Strep)-like organisms, other than Aerococcus spp. (i.e., Enterococcus, Lactococcus, and Streptococcus spp.) were associated with increases in postcalving clinical and subclinical mastitis.
 But infection with NAS species associated with variable effects

Question 281

Longitudinal study of herd udder hygiene and its association with clinical mastitis in pasture-based dairy cows.

Rowe et al., 2021

Answer 281

 Herd udder hygiene assessed at milking was positively associated with clinical mastitis
 At least 80 cows needed to be scored to achieve sufficiently precise estimations of herd udder hygiene
 Cows scored later during the milking order were more likely to have poorer udder cleanliness.

Question 282

Trends in somatic cell count deteriorations in Dutch dairy herds transitioning to an automatic milking system.
van den Borne et al., 2021

Answer 282

 Udder health deteriorations around the transition to an AMS were still observed, although less than historically measured.

Question 283

Monitoring selected behaviours of calves by use of an ear-attached accelerometer for detecting early indicators of diarrhoea. Goharshahi et al., 2021

Answer 283

 Ear tag based smartbow system applied to calves after birth
 Lying and activity times the day before diarrhoea were associated with the odds of diarrhoea occurring the subsequent day

Question 284

In vitro antimicrobial resistance profiles of Streptococcus uberis, Lactococcus spp., and Enterococcus spp. from quarter milk samples of cows between 2015 and 2019 in Southern Germany.
Sorge et al., 2021

Answer 284

 Penicillin should remain the first-choice antimicrobial for the therapy of Strep. uberis and Lactococcus spp. However, a success of any antimicrobial treatment of enterococcal infections seems questionable.

Question 285

Retrospective cohort study of management procedures associated with dairy herd-level eradication of Streptococcus agalactiae in the Danish surveillance program.
Skarbye et al., 2021

Answer 285

 Culling infected cows early in lactation may facilitate herd-level eradication of Strep. Agalactiae
 A higher proportion of culling due to mastitis within 100 d from calving was associated with a higher probability of herd-level recovery from Strep. agalactiae in herds with conventional milking system

Question 286

Particulate matter and airborne endotoxin concentration in calf barns and their association with lung consolidation, inflammation, and infection
Van Leenen et al., 2021

Answer 286

 Exposure to fine (PM1.0μm) particulate matter fractions was associated with increased odds of lung consolidations of ≥1 cm (OR: 3.3), ≥3 cm (OR: 2.8), and ≥6 cm (OR: 12.3).
 The odds of having lung consolidations of ≥1 cm (OR: 13.9) and ≥3 cm (OR: 6.7) were higher when endotoxin concentrations in the dust mass exceeded 8.5 EU/µg.
 Broncho-alveolar lavage fluid neutrophil percentage was positively associated with PM10 concentration
 Concentration of particulate matter 2.5μm was positively associated with epithelial cell percentage and isolation of Pasteurella multocida.
 In this study particulate matter fractions were associated with pneumonia in calves.

Question 287

On-farm detection of claw lesions in dairy cows based on acoustic analyses and machine learning
Volkmann et al., 2021

Answer 287

 Sound of cows walking recorded, machine learning used to predict lameness.
 This model obtained a sensitivity of 0.81 and a specificity of 0.97.
 This study shows that lameness can be detected by machine learning from the impact sound of hoofs in dairy cows.

Question 288

Rumination time around dry-off relative to the development of diseases in early-lactation cows.

Abuelo et al., 2021

Answer 288

 Cows that developed lameness in early lactation showed reduced daily rumination time in the period between +1 and +3 d relative to dry-off.
 Cows that developed lameness in the first 60 d in milk showed reduced RT from 1 to 3 d following dry off compared with cows that were not diagnosed with lameness in early lactation.
 Rumination time around dry off was not associated with the occurrence of mastitis, metritis, retained placenta, hyperketonemia, hypocalcemia, pneumonia, and displaced abomasum

Question 289

Association between early postpartum rumination time and peak milk yield in dairy cows. Peiter et al., 2021

Answer 289

 Average rumination time and change in rumination time over the first 6 d in milk are associated with peak milk yield for multiparous cows, whereas no association was found for primiparous cows

Question 290

Randomized controlled trial assessing the effects of xylazine sedation in 2- to 6-week-old dairy calves disbudded with a cautery iron
Reedman et al., 2021

Answer 290

 Calves sedated with xylazine for cautery disbudding responded less to painful stimuli both during and following the procedure and had a higher rate of play behaviour 24 h following sedation compared with the nonsedated calves, but xylazine may also have a prolonged carryover effect that affects suckling behaviour for 48 h following sedation

Question 291

Association of blood calcium concentration in the first 3 days after parturition and energy balance metabolites at day 3 in milk with disease and production outcomes in multiparous Jersey cows

Neves et al., 2021

Answer 291

 Based on this study, assessments performed at 3 DIM using tCa concentration ≤1.99 mmol/L for increased risk of early-lactation culling and FFA ≥0.43 mmol/L for increased risk of metritis could be used as starting points

Question 292

Partial budget analysis of culture- and algorithm-guided selective dry cow therapy
Rowe et al., 2021

Answer 292

 Culture and algorithm based SDCT approaches associated with financial savings
 The extent of financial savings was reduced if clinical or subclinical mastitis frequency increased after SDCT

Question 293

Monitoring bovine tick fever on a dairy farm: An economic proposal for rational use of medications. Souza et al., 2021

Answer 293

 Protocol: all calves with an increase of 0.5°C in rectal temperature compared with the previous week’s measurement were treated for Anaplasma spp. and Babesia spp
 Over half of treated cases were negative on blood smears
 An optimized protocol would consider rectal temperature and smear results prior to treatment; which would be more economically viable.

Question 294

Physically effective neutral detergent fiber improves chewing activity, rumen fermentation, plasma metabolites, and milk production in lactating dairy cows fed a high-concentrate diet. Cao et al., 2021

Answer 294

 Increasing peNDF8.0 concentration in high-concentrate diets could help alleviate subacute ruminal acidosis by increasing peNDF8.0 intake, chewing activity, and rumen pH. Feed digestibility and plasma metabolites were also enhanced

Question 295

Effect of partial exchange of lactose with fat in milk replacer on ad libitum feed intake and performance in dairy calves

Echeverry-Munera et al., 2021

Answer 295

 Final BW (84 d) did not differ between treatments.
 Overall, calves fed ad libitum seemed to regulate their intake of MR based on its energy density, without significant effects on solid feed intake and overall growth.

Question 296

A retrospective study investigating the association of parity, breed, calving month and year, and previous parity milk yield and calving interval with twin births in US dairy cows

Schambow et al., 2021

Answer 296

 Previous parity milk production was associated with an increased probability of twin births across parity and breed.
 Third and greater parity (3+) compared with second parity (2) and all breeds compared with Jerseys were associated with greater twin probability
 Twin births associated with a lower hazard of subsequent pregnancy

Question 297

Characterization of pregnancy-associated glycoproteins and progesterone as a predictor of twins and conceptus loss in high-risk-pregnancy Holstein cows
Peixoto et al., 2021

Answer 297

 Pregnancy loss and twins were predicted with moderate accuracy by P4 concentration at d 37 post-AI:
 A threshold of 6.5 ng/mL predicted pregnancy loss with an area under the curve (AUC) of 0.64,
 A threshold of 7.2 ng/mL predicted twins with AUC of 0.71.

Question 298

Effects of energy source in milk replacer on glucose metabolism of neonatal dairy calves

Welboren et al., 2021

Answer 298

 The majority of calf milk replacers contain more lactose and less fat than whole milk.
 This study evaluated the effects of partially replacing lactose in milk replacer with fat on glucose metabolism in neonatal dairy calves.
 This resulted in increased body weight gain during the first week of life, and although fasting insulin sensitivity was unaffected, smaller fluctuations in postprandial plasma glucose and insulin were observed and postprandial insulin sensitivity tended to be increased

Question 299

Technical note: Evaluation of a commercial on-farm milk leukocyte differential tester to identify subclinical mastitis cases in dairy cows
Robles et al., 2021

Answer 299

 Correlation coefficients (r) were 0.97 for Total Leukocyte Count (TLC) and SCC and 0.90 for TLS and SCS.
The onfarm milk leukocyte differential tester was precise but not overall accurate for total cell counts; it had high specificity and accuracy for diagnosis compared with
a standard diagnostic tool

Question 300

Short communication: Comparative performance of 3 on-farm culture systems for detection of mastitis pathogens interpreted by trained and untrained observers
Sipka et al., 2021 (Moroni author)

Answer 300

 Three OFC systems:
 Minnesota Easy Culture System II Bi-plate (gram-positive, gram-negative)
 Minnesota Easy Culture System II Tri-plate (gram-positive, gram-negative, some genus level)
 FERA Diagnostics and Biologicals AccuMast plate (genus level, some species level)
 all 3 OFC appeared suitable to support pathogen-based mastitis management when operated by trained observers.
 Training beyond the instruction manual is a prerequisite to make OFC systems useful for pathogen-based mastitis management

Question 301

Short communication: Diagnostic accuracy of focused lung ultrasonography as a rapid method for the diagnosis of respiratory disease in dairy calves
Pravettoni et al., 2021 (Buczinsly author)

Answer 301

 Focused lung ultrasound only considers lung lobes most commonly affected by BRD:
 The caudal aspect of the cranial lobe of the left lung (fifth and fourth left intercostal spaces; ICS)
 The middle lobe of the right lung (fifth right ICS)
 The caudal aspect of the cranial lobe of the right lung (fourth right ICS).
 Pneumonia was diagnosed when a calf had a minimum of one small lobular lung lesion that was at least 1 cm deep within a normally aerated lobe
 Focus Lung US(Flus) had a sensitivity of 81.6% and a Sp of 100%.
 Flus might be of use when examining large numbers of calves, agreeing well with TUS

Question 302

A herd-level study on colostrum management factors associated with the prevalence of adequate transfer of passive immunity in Québec dairy herds
Morin et al., 2021 (Buczinly and Dubuc authors)

Answer 302

 The prevalence of adequate TPI was associated with the prevalence of an adequate colostrum volume fed at first meal (≥2.5L) and the prevalence of an adequate time to first feeding (≤3 h).

Question 303

A calf-level study on colostrum management practices associated with adequate transfer of passive immunity in Québec dairy herds
Morin et al., 2021 (Buczinly and Dubuc authors)

Answer 303

 Increased odds of adequate transfer of passive immunity associated with:
 Calves receiving ≥2.5 L colostrum at their first meal
 Calves receiving colostrum with ≥24.5% Brix
 Calves receiving colostrum within 3 h after birth
 Total bacteria count and TCC were not associated with the odds of adequate transfer of passive immunity

Question 304

Molecular epidemiology, antimicrobial activity, and virulence gene clustering of Streptococcus agalactiae isolated from dairy cattle with mastitis in China. Lin et al., 2021

Answer 304

 Majority of isolates belonged to the clonal complex CC103
 Most isolates were susceptible to β-lactams

Question 305

Risk and success factors for good udder health of early lactation primiparous dairy cows

Persson Waller et al., 2021

Answer 305

 Factors associated with a low SCC in primiparous cows included:
 Having an SOP for colostrum feeding
 Lower mean bulk SCC
 Lower overall culling rate due to udder health
 Not using automatic milking

Question 306

Changes in the soft-tissue thickness of the claw sole in Holstein heifers around calving

Bach et al., 2021

Answer 306

 Claw horn disruption lesions develop due to excessive pressure from the distal phalanx on the horn-producing tissue in the sole
 Measured the thickness of the soft tissue between the pedal bone and the sole horn on all weight-bearing hind claws of 34 heifers 4 times during the weeks before and after calving.
 We showed that the pedal bone was sinking from 10 d before to 5 d after calving.
 Solar thickness decreased when measured precalving and postcalving, associated with rotation of the distal phalanx toward the posterior part of the sole horn in the weeks around calving
 There was NO correlation between BCS and solar soft tissue thickness.

Question 307

Associations between differential somatic cell count and milk yield, quality, and technological characteristics in Holstein cows
Pegolo et al., 2021

Answer 307

 Differential somatic cell count represents the combined proportions of polymorphonuclear neutrophils plus lymphocytes (PMN-LYM) in the total somatic cell count (SCC).
 Differential somatic cell count was also positively associated with the recovery of milk nutrients in the curd (protein, fat, and energy), which increased linearly with increasing DSCC

Question 308

Mycoplasma species isolated from bovine milk collected from US dairy herds between 2016 and 2019
Gioia et al., 2021

Answer 308

 Whilst M. bovis was the most common, 21% of mastitis cases contained other Mycoplasma spp.
 Mycoplasma bovis was the most prevalent Mycoplasma species (75.1%), followed by M. bovigenitalium (6.5%), M. canadense (5.9%), M. alkalescens (5%), M. arginini (1.7%), M. californicum (0.1%), and M. primatum (0.1%)
 Our results suggest that it is critical to test milk samples for mycoplasmas using diagnostic tests able to identify both the genus and the species

Question 309

Functional foot trimming to balance load distribution between the paired forelimb claws in dairy cows: An experimental study

Luchinger et al., 2021 (Nuss author)

Answer 309

 Measured force, contact areas and pressures on sound and lame cows, after trimming and with plywood plates attached to claws
 After foot trimming, medial forelimb claw carried 70% of the entire forelimb load, with the palmar zone bearing 54% of the entire load and the greatest forces/pressures.
 3mm plywood plates attached to the lateral claw only resulted in a more even load distribution
 Equal load distribution between the forelimb claws was achieved in our setting when the lateral claws were left 3 mm higher than the medial claws.

Question 310

Immunization with a novel recombinant protein (YidR) reduced the risk of clinical mastitis caused by Klebsiella spp. and decreased milk losses and culling risk after Escherichia coli infections

Tomazi et al., 2021

Answer 310

 The rYidR vaccine reduced the risk of CM caused by Klebsiella spp. and the mortality or culling of cows with CM caused by E. coli.
 Additionally, cows immunized with rYidR produced more milk and had higher conception risk at the first service compared with cows injected with a placebo or a commercially available vaccine.

Question 311

Type of teat cup liner and cluster ventilation affect vacuum conditions in the liner and milking performance in dairy cows
Holst et al., 2021

Answer 311

 Higher system vacuum caused faster milk removal in all liner and ventilation types.
 Round liners milked faster than triangular liners at simultaneously lower mouthpiece chamber vacuum.
 Mouthpiece chamber ventilation caused lower mouthpiece chamber vacuum with stronger fluctuations compared with claw ventilation in both liner types.
 However, milking performance was not affected by the type of cluster ventilation

Question 312

Associations between body condition score, locomotion score, and sensor-based time budgets of dairy cattle during the dry period and early lactation
Hut et al., 2021

Answer 312

 Compared with sound cows, daily eating time differed by –20 min and –38 min for moderately (Score 3/5) and severely lame (score 4 or 5/5) cows, respectively.
 Lame cows also lied down for longer and walked less steps
 A loss in body condition during early lactation was associated with increased lameness postpartum in multiparous cows.

Question 313

Quantification of antimicrobial usage in adult cows and preweaned calves on 40 large Wisconsin dairy farms using dose-based and mass-based metrics

Leite de Campos et al., 2021

Answer 313

 When using a dose-based metric, intramammary antimicrobials represented the greatest proportion of antimicrobials used, whereas using a mass-based metric, systemic antimicrobials represented the greatest proportion of antimicrobials used.
 These results showed that choice of metric can substantially alter interpretations about quantities and routes of antimicrobials administered on dairy farms.

Question 314

Measuring antimicrobial use on dairy farms: A method comparison cohort study

Rees et al., 2021

Answer 314

 Waste bins on farms for 12 months compared to farm medicine records and vet sales data
 Although no method was perfect, by comparing the results of veterinary sales data, on-farm medicine records, and on-farm medicine waste bins, we concluded that veterinary sales data agreed best with the reference method used

Question 315

Survey of veterinarians in the Netherlands on antimicrobial use for surgical prophylaxis in dairy practice
Jorritsma et al. 2021

Answer 315

 When preoperative prophylaxis was applied, the choice of (combinations of) the AM and the timing of administration were not adequate at the start of the surgical procedure (88% for CS and 90% for LDA).
 We conclude that considerable qualitative (timing, choice of antimicrobial, route of administration) and quantitative (limit AMU to indicated procedures) improvement on antimicrobial prophylaxis for CS and LDA is possible by appreciation of the risks of the type of surgery (CS, LDA) and its conditions as well as by selecting classes of AM and timing and routes of administration that result in effective drug concentrations at the start of the procedure.

Question 316

Accuracy of direct and indirect methods for assessing bovine colostrum quality using a latent class model fit within a Bayesian framework

Elsohaby et al., 2021 (Buczinsky author)

Answer 316

 Using a threshold of <23% for digital Brix refractometer and <50 g/L for RID and TIR spectroscopy, median Se estimates were
 23% Brix - 73.2
 <50g/L RID - 86.2
 <50g/L TIR - 91.9%
 Median Sp estimates were
 23% Brix – 85.2
 <50g/L RID – 99.4
 <50g/L TIR – 90.7%
 A suggested Brix threshold of >23% could reduce feeding of low-quality colostrum to calves
 TIR spectroscopy showed high Se in detection of low-quality colostrum.
 The RID assay, which is used as the reference test in several studies, showed limited Se for detection of low-quality colostrum.

Question 317

Association of subclinical hypocalcemia dynamics with dry matter intake, milk yield, and blood minerals during the periparturient period

Seely et al., 2021 (Overton,McArt authors)

Answer 317

 Transient subclinical hypocalcaemia (tSCH) – physiological
 Transiently subclinical cows experienced a significant blood calcium drop within the first day after calving but then recovered quickly.
 Persistent subclinical hypocalcaemia (pSCH) – pathological
 Persistently subclinical cows had a small but extended drop in blood calcium
 Delayed subclinical hypocalcaemia (dSCH) – pathological
 Delayed subclinical cows had a significant blood calcium drop and slow recovery

 There was higher DMI and milk yield in cows that remained normocalcemic or experienced a transient reduction in plasma calcium following calving.
o No differences in prepartum feed intakes
o Normocalcaemic and transient SCH cows consumed more feed than the pSCH or the dSCH during the first 3wk of lactation
Have a look paper for threshold!!!

Question 318

Body condition loss during the dry period: Insights from feeding behaviour studies

Daros et al., 2021

Answer 318

 overconditioned (≥3.5)
 The BCS at dry-off was associated with changes in feeding behaviour, such that overconditioned cows had lesser daily DMI and feeding time during the early and late dry periods compared with not overconditioned animals.
 We also noted an effect of previous 305-d milk yield on DMI; cows that produced more milk had greater DMI throughout the dry period. The ΔBCS was only partially mediated by DMI, and BCS at dry-off still had a direct effect on ΔBCS. This result indicated that mechanisms other than DMI were associated with BCS loss during the dry period.
 Strategies to improve intake during the dry period should take dry-off BCS into account or, preferably, efforts should be made to minimize the number of overconditioned cows at the end of lactation.

Question 319

Effects of a mastitis treatment strategy with or without on-farm testing

Griffoen et al., 2021

Answer 319

 2 on-farm tests used: CHROMagar Mastitis or Minnesota easy culture Tri-plate which discriminated gram positive, gram negative and culture negative.
 Clinical cure rate, percentage of new IMI, and SCC on d 21 of clinical mastitis were comparable among the groups – using on farm kits led to more treatments in accordance with the aetiology of mastitis by farmers
 For subclinical mastitis, antimicrobial usage was much higher in cases using either culture system than the controls
 For subclinical mastitis, on-farm testing may lead to an unacceptable increase in use of antimicrobials and thus should not be advised as the common approach

Question 320

The occurrence of methicillin-resistant non-aureus staphylococci in samples from cows, young stock, and the environment on German dairy farms

Schnitt et al., 2021

Answer 320

 Nine MR-NAS species were identified; Staph. sciuri, Staph. lentus, Staph. fleurettii, Staph. epidermidis, and Staph. haemolyticus were the most common species.
 Resistance genes may be transferred between NAS and Staph. aureus on the respective farms.

Question 321

Prepartum behaviour changes in dry Holstein cows at risk of postpartum diseases

Belaid et al., 2021

Answer 321

 Prepartum behaviour of cows affected with metritis, DA, and ketosis was different from that of cows not diagnosed with diseases during the 1wk prepartum:
 Cows with metritis had more lying bouts (+21%)
 Cows with DA had fewer meals (−24%) and tended to take fewer steps (−18%)
 Cows with ketosis had fewer meals (−22%) and spent less time at the feed bunk (−40%).

Question 322

Intergenerational cycle of disease: Maternal mastitis is associated with poorer daughter performance in dairy cattle

Swartz et al., 2021

Answer 322

 The association of greater dam mean SCS with lesser daughter milk fat yield is likely due to a few underlying mechanisms, in particular, a predisposition for mastitis and alterations in the epigenome controlling milk fat synthesis

Question 323

Effects of milk feeding strategies on short- and long-term productivity of Holstein heifers

Garcia et al., 2021

Answer 323

 Failing to pasteurize nonsaleable milk and colostrum had a detrimental influence on performance of heifers with low birth weight, which remained apparent for more than 2 yr.
 For the first 42 d of life, low birth weight heifers fed pasteurized versus raw NSM had greater weight gain, grain intake, and feed efficiency and were weaned earlier
 During the first lactation low birth weight heifers fed raw nonsaleable milk produced less milk, MP, MF compared to those fed pasteurized NSM or MR.

Question 324

Different feed presentations affect subsequent feed sorting and rumen pH for a short period in weaned calves

Xiao et al., 2021

Answer 324

 Calves fed the concentrates only had lower DMI and ADG than the other two groups
 There were no performance differences between calves fed the hay + concentrate separately or mixed
 Calves fed the mixed ration developed a higher degree of sorting against long fractions, which persisted in the short term during TMR feeding
 By the end of the experiment (wk 28), feed sorting and rumen pH were similar across all treatments.

Question 325

Preweaning to postweaning rumen papillae structural growth, ruminal fermentation characteristics, and acute-phase proteins in calves
Van Niekerk et al., 2021

Answer 325

 Around weaning a prolonged ruminal pH depression was observed: dietary rumen adaptation after weaning can take several weeks in calves with a high MR feeding rate preweaning.

Question 326

Timing of artificial insemination using fresh or frozen semen after automated activity monitoring of oestrus in lactating dairy cows
Tippenhauer et al., 2021

Answer 326

 Cows inseminated from 7 to 24 h after onset of oestrus or from 1 to 18 h after peak of oestrus activity showed greatest pregnancy per AI irrespective of type of semen.

Question 327

Efficacy of a second intrauterine cephapirin infusion for the treatment of purulent vaginal discharge and endometritis in postpartum dairy cows
Dubuc et al., 2021

Answer 327

In cows affected by ENDO, a second treatment also increased the pregnancy risk at first insemination compared with
cows that only received one treatment (30.3 vs. 39.2%).
Overall, these results demonstrate that administering a second intrauterine cephapirin infusion 14 d after the
initial treatment in postpartum cows affected by PVD or ENDO did improve their subsequent reproductive performance.

Question 328

Associations of serum biomarkers of stress and inflammation measured at arrival with health, mortality, and growth of calves transported within the first 4 days of life
Celestino et al., 2021

Answer 328

 Calves with Hp concentration ≤0.63 μmol/L at arrival were more likely to be diagnosed with BRD (and tended to have lower ADG) during the preweaning period
 Hp was not associated with mortality
 Circulating concentrations of l-lactate and cortisol measured at arrival were not associated with BRD incidence during the preweaning period

Question 329

Molecular diversity of Staphylococcus aureus and the role of milking equipment adherences or biofilm as a source for bulk tank milk contamination
Pacha et al., 2021

Answer 329

 The discovery of common pulsotypes among milking equipment samples from different farms consistently sharing Staph. aureus with bulk tank milk samples shows the role of milking equipment as a source of Staph. aureus in on-farm bulk tank milk contamination

Question 330

Provision of shelter during the prepartum period: Effects on behaviour, blood analytes, and health status in dairy cows in winter
Cartes et al., 2021

Answer 330

 Sheltered cows were cleaner, spent more time lying down, and showed fewer signs of fat mobilization than cows without access to shelter during the prepartum period (lower NEFA and haptoglobin precalving and postcalving respectively).
 The provision of shelter mitigates the effects of winter weather, promoting the welfare of prepartum dairy cows.

Question 331

The effect of individual versus pair housing of dairy heifer calves during the preweaning period on measures of health, performance, and behaviour up to 16 weeks of age
Knauer et al., 2021 (Godden author)

Answer 331

 Pair housing of dairy heifer calves during the preweaning period helps meet the natural social needs of the calf and has been shown to improve growth and starter intake during the preweaning period as compared with individual housing.
 Calves raised individually or in pairs up until 16wks of age.
 Pair raised calves were heavier at weaning and gained 150g/d more per day than the individually reared calves
 During weaning pair raised calves had increased lying times.

Question 332

Familiarity influences social networks in dairy cows after regrouping
Foris et al., 2021

Answer 332

 cows preferred familiar individuals as grooming partners and feeding neighbors directly after regrouping and 1wk later
 Familiar cows displaced each other at the feed bunk more than unfamiliar ones, possibly because they were neighbors more often
 A small group of familiar cows may provide ongoing social buffering after regrouping.

Question 333

Progression of different udder inflammation indicators and their episode length after onset of inflammation using automatic milking system sensor data.
Bonestroo et al., 2021

Answer 333

 On average, for cows that did recover, the inflammation indicators recovered within 3 to 4 wk after the initial udder inflammation
 A cutoff point between nonchronic and chronic changes in indicators of 3 to 4 wk after the initial inflammation for SCC and σ-conductivity is suggested

Question 334

Dynamics of somatic cell count (SCC) and differential SCC during and following intramammary infections
Kirkeby et al., 2021

Answer 334

 Both SCC and DSCC increased after IMI, with a more pronounced increase if major or other pathogens were detected compared with minor pathogens.
 Major pathogens had the longest-lasting effect in both herds for both SCC and DSCC.

Question 335

The nasopharyngeal microbiota of preweaned dairy calves with and without ultrasonographic lung lesions

Raabis et al., 2021 (Ollivett author)

Answer 335

 pneumonia was defined as having lobar pneumonia, as diagnosed by US, in at least 1 lung lobe.
 Severity of pneumonia was associated with an increased relative abundance of Pasteurella spp. in the nasopharynx.
 Increased microbial diversity of the nasopharynx may be associated with reduced prevalence of clinical BRD

Question 336

Making tiestalls more comfortable:
I. Adjusting tie-rail height and forward position to improve dairy cows’ ability to rise and lie down
St John et al., 2021

Answer 336

 (I) We tested 4 tie-rail positions, including 2 novel tie-rail placements, and found that injury prevalence changed based on the location of the tie-rail.

Question 337

Making tiestalls more comfortable

II. Increasing chain length to improve the ease of movement of dairy cows

Answer 337

 (II) Compared the effect of a tie chain longer than the current recommendation on the ease of movement of dairy cows housed in tiestalls
 Increasing chain length leads cows to modify the way they use the available space and improves their ease of movement upon lying down.
 Increasing chain length could be implemented as a low-cost modification on tiestall dairy farms as part of a series of measures aiming to improve comfort of dairy cow at their stalls.

Question 338

Making tiestalls more comfortable:
III. Providing additional lateral space to improve the resting capacity and comfort of dairy cows

Question 339

Making tiestalls more comfortable:
III. Providing additional lateral space to improve the resting capacity and comfort of dairy cows

Answer 339

 (III) Compared the effect of housing lactating dairy cows in tiestalls of double width compared with the current recommendation
 Increasing stall width improves the cows’ comfort and resting capacity by providing them with increased opportunities to express and switch between natural lying postures.
 Increasing stall width also reduced the prevalence of contacts with the stall elements during lying-down movements,

Question 340

Making tiestalls more comfortable:
IV. Increasing stall bed length and decreasing manger wall height to heal injuries and increase lying time in dairy cows housed in deep-bedded tiestalls

Answer 340

 (IV) Tested the effect of stall length and manger wall height on dairy cows housed in deep-bedded tiestalls.
 Increasing stall length increased lying time and allowed for healing of pre-existing injuries. Manger wall height may play a role in how the cow positions herself in the stall.

Question 341

Negatively controlled, randomized clinical trial comparing different antimicrobial interventions for treatment of clinical mastitis caused by gram-positive pathogens

Tomazi et al., 2021

Answer 341

 4 treatment protocols:
 3x 62.5mg amoxicillin 12hrs apart
 5x 62.5mg amoxicillin 24hrs apart
 5x 125 mg of ceftiofur hydrochloride 24hrs apart
 No treatment
 Streptococcus uberis, followed by Streptococcus dysgalactiae, were the main causes of gram-positive CM.
 The 2d protocol had similar bacteriological/clinical cures the 5d protocol
 5d protocols were more effective at reducing milk cfu counts
 Antibiotic use remains an indispensable strategy for treatment of CM caused by gram-positive bacteria.

Question 342

Sensitivity and specificity of a tail-activity measuring device for calving prediction in dairy cattle
Voß et al., 2021

Answer 342

 In 31 animals the sensor was removed because the tail was swollen or painful.
 Depending on the interval preceding the onset of parturition, sensitivity varied from 19 to 75% and specificity from 63 to 96%.

Question 343

Effects of herd fertility on the economics of sexed semen in a high-producing, pasture-based dairy production system
Walsh et al., 2021

Answer 343

 The profitability of sexed semen was primarily dependent on the baseline fertility of the herd, as well as calf prices

Question 344

The economic cost of metritis in dairy herds
Perez-Baez et al., 2021

Answer 344

 Metritis was defined as fetid, watery, red-brownish vaginal discharge that occurs ≤21 d in milk.
 Milk yield and proportion of cows pregnant were lesser for cows with metritis than for cows without metritis
 The proportion of cows leaving the herd was greater for cows with metritis than for cows without metritis.
 The mean cost of a case of metritis was $513
 Main costs were associated with decreased milk production, reproduction, and survival in the herd.

Question 345

Economic losses due to Johne’s disease (paratuberculosis) in dairy cattle

Rasmussen et al., 2021

Answer 345

 It was estimated that approximately 1% of gross milk revenue, equivalent to US$33 per cow, is lost annually in MAP-infected dairy herds, with those losses primarily driven by reduced production

Question 346

Influence of starter crude protein content on growth and body composition of dairy calves inan enhanced early nutrition program.

Stamey Lanier et al., 2021

Answer 346

At 5wks carcasse weight was not different for both groups fed high MR rate
 Feeding a starter with higher crude protein increased growth of the reticulorumen and liver without affecting empty body weight gain.
 Feeding the larger amount of milk replacer with the lower protein starter increased fat content of empty body weight gain after weaning, but the higher crude protein starter resulted in less fat in gain.

Question 347

Addition of straw to the early-lactation diet: Effects on feed intake, milk yield, and subclinical ketosis in Holstein cows.
Seifi et al., 2021

Answer 347

 Compared this conventional approach with a feeding protocol that supplemented the diet with chopped straw, diluting the energy density and increasing the physically effective fibre.
 Adding straw to the diet of lactating cows reduced feed intake and milk yield and increased the incidence of subclinical ketosis during early lactation.

Question 348

Effects of prepartum diets varying in dietary energy density and monensin on early-lactation performance in dairy cows

Vasquez et al., 2021 (Drackley author)

Answer 348

 Monesin or not monesin bolused, two different dry cow strategies, monesin fed during lactation:
 CE = Controlled energy diet throughout the DP
 CU = controlled-energy diet from dry-off to 22 d before expected parturition, followed by a moderate-energy close-up diet from d 21 before expected parturition through parturition
 Diet had little effect on subsequent lactation performance:
 Milk fat and lactose content were greater for cows fed CU than for those fed CE
 Lactose content and yield were increased for cows supplemented with MON

Question 349

Evaluation of solar photovoltaic systems to shade cows in a pasture-based dairy herd

Sharpe et al., 2021

Answer 349

 Cows with access to solar shade had similar behaviour characteristics, fly counts, and milk production compared with cows with no access to shade.
 Shade cows had lower body temperatures and respiration rates between milking’s at the hottest parts of the day
 Incorporating solar photovoltaic into pasture dairy systems may reduce intensity of heat stress in cows.