Preventive Veterinary Medicine Flashcards

Question

Associations between different udder health groups defined based on a combination of total and differential somatic cell count and the future udder health status of dairy cows Schwarz et al., 2021

Answer 1

 Four udder health groups based upon SCC and DSCC:  A: healthy/normal, ≤200,000 cells/mL and DSCC ≤65 %;  B: suspicious, ≤200,000 cells/mL and DSCC >65 %;  C: (subclinical) mastitis, >200,000 cells/mL and DSCC >65 %;  D: chronic/persistent mastitis, >200,000 cells/mL and DSCC ≤65 %.  Cows in groups C (OR: 2.13, CI: 1.95–2.34) and, particularly, D (OR: 3.91, 95 % CI: 3.31–4.62) were significantly more likely to leave herds compared to cows in group A.  Late-lactating cows indicated the highest likelihood (OR: 16.03, 95 % CI: 14.44–17.81) to leave herds in our analysis.  Interestingly, we found that cows in UHG B had significantly higher odds (OR: 2.77, 95 % CI: 2.58–2.98) to have >200,000 cells/mL at the next test day compared to cows in group A.  As anticipated, cows in UHG B (OR: 0.40, 95 % CI: 0.38–0.42), C (OR: 0.08, 95 % CI: 0.07–0.09), and D (OR: 0.16, 95 % CI: 0.14–0.19) each were significantly less likely to have ≤200,000 cells/mL at the next 3 test days compared to cows in group A In conclusion, our findings illustrate that the UHG concept reveals additional valuable information about udder health and culling based a single test day over working with SCC only. Actual decisions in day-to-day farm management that could be taken were not investigated here and need to be further explored.

Answer 2

 Transmission rate:  Staph. aureus: range of 0.002 (95 % CI: 0−0.005) quarter-day−1 to 0.019 (95 % CI: 0.010−0.032) quarter-day−1  Strep. Agalactiae: range of 0.007 (95 % CI: 0.005−0.010) quarter-day−1 to 0.019 (95 % CI: 0.011−0.032) quarter-day−1,  Mean duration of chronic IMI  Staph aureus: 95 (95 % CI: 72−125) days  Strep agalactiae: 86 (95 % CI: 67−111) days  R0  Staph aureus: between 0.16 (95 % CI: 0.05−0.27) and 0.34 (95 % CI: 0.20−0.48)  Strep agalactiae: between 0.64 (95 % CI: 0.41−0.87) and 0.68 (95 % CI: 0.48−0.88)  The estimated transmission rate of Staph. aureus in this AMS herd was found to be comparable to those described for CMS herds, while for Strep. agalactiae, it was slightly higher than in CMS herds.  The duration of Staph. aureus IMI was in line with results from CMS farms, while the duration of Strep. agalactiae was lower than what has been described in CMS herds.  The R0 of these contagious pathogens was found to be lower than the estimates in CMS herds.

Answer 3

 Herd seropositive status for BRSV was associated with lower mean age of culling  Herds with BSRV-seropositive youngstock had increased culling rate.  There was also a tendency of BVDV-negative herds to have a lower CR than BVDV-positive herds  MAP-positive hers had somewhat lower herd mean age of culled cows  Vaccination against BVDV tended to be protective against high culling rate vs infected herds This study shows that Estonian large-scale dairy herds are endemically infected with several important cattle pathogens. Most of the studied pathogens influence longevity and culling rates, thus entailing health and economic consequences.

Answer 4

 Cows born in September and born out of heifers to have the highest odds to become a HT.  When cows received a score ≥ 83 (population average 80) for udder and feet & legs conformation, they had higher odds of reaching the 100,000 kg threshold.  While a greater body condition and larger rump angle increased the odds of becoming a HT, this was decreased in cows with a large body depth.  Breeding values for milk yield, fertility, udder health and claw health were positively associated with the likelihood of reaching a lifetime milk yield of 100,000 kg.  In conclusion, to increase lifetime milk yield in dairy herds, farmers should select heifers with high scores for conformation traits like udder and feet & legs and high breeding values for milk yield, fertility and udder health.

Answer 5

 Elevated mastitis risk perceptions were linked to an increased readiness to milk record.  However, this relationship was not universal across all farmers.  One segment of farmers in the current study maintain low mastitis risk perceptions and remain unmotivated to engage in milk recording.  The types of risk communication strategies – message framing and two-way risk communication – should reflect farmers’ types of mastitis risk perceptions to have the most effective impact on milk recording uptake

Answer 6

 Average calf mortality on Finnish calf rearing farms was 4.5 %  Application of the all in/all out principle and proper washing and disinfection of compartments for milk feeding calves between arrival batches, were associated with lower mortality and increased daily gain.  Higher arrival age was associated with lower mortality during the rearing period and relatively higher arrival age of the calf, compared to other calf in a same arrival batch, was associated with higher daily gain.  Increased number of individual medications during the rearing period was associated with both increased mortality and decreased daily gain.  There was no significant difference in mortality between farm types

Answer 7

 Severely lame cows spent 4.5 times less time grazing and almost twice as much time resting as their sound congeners, especially in the lying position.  Exploratory behaviour was also reduced for both moderately and severely lame cows, resulting in 1.2 and 1.7 times less distance travelled respectively, especially during grazing.  These variables could be used as additional variables to improve the performance of existing lameness detection devices in pasture-based systems.

Answer 8

 Participants viewed antibiotic overuse as largely due to farmers’ concern for the welfare of their cattle and desire to treat ailments swiftly.  Interviewees believed that it was possible to reduce antibiotic use through regulation, such as the Veterinary Feed Directive and improved herd management activities, such as better colostrum management.  They did not view the dairy industry as a significant contributor to AMR, particularly when compared to the human medical industry.

Answer 9

 In a fixed time window of day -5 to 30 around the first treatment, the absolute median milk losses per case were 101.5 kg, highly dependent on the parity and the lactation stage with absolute milk losses being highest in multiparous cows and at peak lactation.  Relative milk losses expressed in percentage were highest on the first treatment day, and full recovery was often not reached within 30 days from treatment onset.  In 62 % of the cases, we found a perturbation in milk yield at the cow level at the time of treatment.  On average, perturbations started 8.7 days before the first treatment and median absolute milk losses increased to 128 kg of milk per perturbation.  Median absolute losses in a fixed 36-day window around treatment varied between 50.2 kg for front and 59.3 kg for hind inflamed quarters compared to respectively 24.7 and 26.3 kg for the median losses in the non-inflamed quarters.  Expressed proportionally to expected yield, the relative median milk losses in inflamed quarters on the treatment day were 20 % higher in inflamed quarters. This analysis confirms the high impact of mastitis on milk production, and the large variation between quarter losses illustrates the potential of quarter analysis for on-farm monitoring at farms with an automated milking system.

Answer 10

 The overall quality of evidence at the outcome level was assessed as being very low.  On average, the treatment effect on immunoglobulin G (IgG), serum amyloid A (SAA), haptoglobin (Hp) and β-hydroxybutyrate (BoHB) for cows receiving probiotics did not differ from control cows.  Exposure to probiotics was not associated with reduced risk of reproductive disorders (pooled RR = 1.02 95 % CI = 0.81-1.27, P = 0.88).  There is insufficient evidence to support any significant positive effects of probiotics on cattle immunity and disease prevention.  This lack of consistent evidence could be due to dissimilarities in the design of the included studies such as differences in dosage, dose schedule, diet composition and/or physiological state of the host at the time of treatment.

Answer 11

 Farm location, farm grazing area, farmer-reported dust levels, fly levels, rain levels, animal zebu content and cattle age were significantly associated with pinkeye prevalence.  Having a farm located in southern Australia, of smaller grazing area with cattle ≤ 2 years of age, was associated with a higher pinkeye prevalence.  Pinkeye prevalence was also greater if respondents ranked their farms as having high fly levels, on farms ranked low for rainfall and on farms ranked as having high dust levels, but moderate dust levels were protective compared to low dust levels

Answer 12

 We built models containing: routinely-available data [lactation number (1, 2, ≥3), calf sex, still birth, twining, dystocia, vaginal laceration score, days on the close-up diets], body condition score (BCS) and BCS change from enrollment to calving (ΔBCS), behavior (feeding, rumination, idle, and active time), and their interactions.  The area under the curve (AUC) of the models including the above with behavior data at 2 DIM to predict metritis [AUC = 0.82, 95% confidence interval (CI) = 0.78, 0.85] and acute metritis (AUC = 0.87, 95% CI = 0.83, 0.89) were (P < 0.01) excellent  The models predicting cure (AUC = 0.92, 95% CI = 0.85, 0.95) and failure (AUC = 0.90, 95% CI = 0.84, 0.94) were outstanding.  Behavioral changes peripartum contribute for the identification of cows at risk for metritis, allowing the development of preventive strategies. In addition, predicting whether cows will respond to antimicrobial treatment.

Answer 13

 Mean OPG higher in younger animals: Animals up to 14 months had a mean total OPG counts higher than older animals (after 15–16 months of age).  E. zuernii and E. bovis were more frequently identified,  E. zuernii was more frequent in animals from 1 to 2 months of age  E. bovis prevailed from three months old.  Both Mcmaster and FLOTAC techniques can be used for quantification of the excretion of oocysts of Eimeria spp. in cattle feces showing the same OPG mean count (r = 0.9287; p = 0.0025; R² = 0.8625).

Answer 14

 The main isolated agents were Streptococcus spp. (n = 54, 30.5 %) and coagulase-positive Staphylococcus (CPS) (n = 54; 30.5 %).  High levels of antibiotic resistance were detected to many antimicrobials  Neither production systems (p = 0.26) nor farming systems (p = 0.24) significantly affected the resistance rates of samples.  Therefore, intensive production systems may not be a root cause of increased rates of antimicrobial resistance in the milk production chain, suggesting that other environmental factors should be investigated.

Answer 15

 Quarter-milk culture Petrifilm: Se82.2%, Sp 62.0%  Quarter-milk standard bacteriology: Se 67.4%, Sp 79.6%  For **first parity cow**s, using only the last Dairy Herd Improvement (DHI) test SCC with a threshold of **100,000 cells/mL**: Se 85.6%, Sp 86.0%, PPV 58.0%, NPV 96.4% and reduction of antimicrobial usage 75.3%.  For **cows of ≥ 2nd parity**, using only the last DHI test SCC with a threshold of **200,000 cells/mL** resulted in Se 75.3%, Sp 84.0%, PPV 47.2%, NPV 94.7% and reduction of antimicrobial usage 77.0%.  Adding quarter-level milk culture using Petrifilm® to cows identified as unhealthy using cow-level SCC data improved the test accuracy (mainly the PPV) and further reduced the use of antimicrobials. (e.g. in ≥ 2nd parity cows increased reduction from 77.0% to 89.5%)  Considering the availability of SCC data, the easiness of using just the last DHI test, and the high NPV that could be achieved, producers may consider using just the last DHI test as a potential tool to identify cows that should be treated with antimicrobials at dry off.  It may be used alone or in combination with quarter-level on-farm Petrifilm® milk culture on high SCC cows to further reduce the use of antimicrobials by identifying quarters that need to be treated.

Answer 16

To compare the impact of the functional hoof trimming (HT) method to an adaptation that results in increased modelling of the weight bearing claw on time to lameness and lesion prevalence in housed dairy cows  Three groups  TRIM1: Dutch 5 step method (DFSM)  TRIM2: DFSM but with increased modelling of the weight bearing claw  CON: negative untreated control  The overall incidence rate of lameness was 29.3 cases/100/month  Prevalence of hoof lesions in the study population was 36.3 %, with the highest prevalence in CON (45.6 %), followed by TRIM1 (34.6 %) and TRIM2 (28.1 %).  The risk of new lameness event was higher in cows with low BCS (≤2.5) (Hazard ratio; HR = 1.5; 95 % CI 1.1–2.1), while trimming all feet was a protective factor (HR = 0.58; 95 % CI 0.38–0.90)  Time to first lameness event was higher in TRIM2 (mean ± S.E; 8.26 ± 0.16, P = 0.03) than CON (7.32 ± 0.2) and tended to be higher than TRIM1 (7.83 ± 0.19; P = 0.07). Our results suggest that the adaptation to the functional method reduced the risk of lameness during lactation, however, proper management of under-conditioned cows is equally important.

Answer 17

 The odds of postpartum lameness were higher for cows that were lame during the prepartum period, had elevated prepartum NEFA concentrations, had greater parity, and for cows that were kept in paddocks with no grass cover.  The odds of metritis were higher in cows with lower parity, with increased prepartum NEFA, in cows that had dystocia, and farms with predominantly Holstein breed, and that did not have calving records.  The odds of clinical mastitis were higher for cows lame during the prepartum period.  The odds of Ca imbalance were higher in cows with a long dry period, dystocic calving, and in farms without prepartum anionic salts supplementation.  The odds of Mg imbalance were higher in cows with lower prepartum Mg concentrations, higher prepartum Ca concentration, and higher parity. Our findings indicate that farmers could benefit from refining these areas to improve their cows' health and welfare.

Answer 18

 The general 3- group classification tree was 52.7 % accurate and had a sensitivity of 81.5 % and a specificity 52.2 % for viruses, respectively 51.7 % and 84.4 % for M. bovis and 28.9 % and 93.6 % for Pasteurellaceae. The single-pathogen trees were more specific than sensitive: Histophilus somni (Se = 25.8 %; Sp = 94.5 %), Mannheimia haemolytica (Se = 69.2 %; Sp = 70.6 %), bovine coronavirus (Se = 42.2 %; Sp = 89.6 %) and bovine respiratory syncytial virus (Se = 34.0 %; Sp = 96.6 %).  For Pasteurella multocida, M. bovis and parainfluenzavirus type 3 no meaningful tree was obtained.  The concept and trees are promising, but currently lack sensitivity and specificity in order to be a reliable tool for practice

Answer 19

 Feeding HS diet significantly affected the proportion of cows cycling by 30 and 40 DIM.  Number of services per conception and calving interval (CI) were significantly improved in cows fed the HS compared to the NS diet (2.08 vs. 2.51 and 427.14 vs. 445.30 days for cows fed HS and NS diets, respectively).  Feeding higher starch diets from 16 till 50 DIM could be an effective strategy to improve the economic variables related to reproduction in dairy cows.

Answer 20

 Median cow-level true prevalence of IAI was 4.4 % (BPI; 1.7–9.0 %).  Median Se and Sp estimates for milk progesterone, at a threshold concentration of ≥ 5 ng/mL were 83.0 % (BPI; 65.0–96.2 %) and were 97.4 % (BPI; 94.6–99.6 %), respectively. The present study estimates that the overall cow-level true prevalence of IAI in Irish dairy cows is relatively low. This is the first study to report the cow-level true prevalence of IAI using a Bayesian latent class model.

Answer 21

 There were significant differences in antibiotic use measured by the bins and the medicine records  Bins were 67 % (CI = 29–87 %) more likely to measure more antibiotic use than the medicine records.  On mixed species farms, 28 % of treatment entries were missing the species the antibiotic was used in.

Answer 22

 Introduction of cattle from a positive herd was associated with increased risk of infection by S. agalactiae in the next year  There was strong association between the cattle movement network and new infections.  At strain-level, new infections with ST1 between 2009 and 2010 were significantly associated with cattle movements.  Sharing of veterinary services, which may serve as proxy for local or regional contacts at a range of scales, was not significantly associated with increased risk of introduction of S. agalactiae or one of the three predominant strains on a farm  Our findings support the reinstatement of restrictions on cattle movements from S. agalactiae positive herds

Answer 23

 FPT:  Female calves were more negatively impacted by failure of transfer of passive immunity compared to male calves.  The odds ratios comparing failure of transfer of passive immunity in BRD score positive calves versus controls for male calves was 1.34 (95 % CI: 0.87, 2.06) and was 2.47 (95 % CI: 1.54, 3.96) for female calves  Age and rearing facility were also associated with risk of BRD Results from both study designs showed the difference in relative contributions of age, sex, immune status, and pathogens in BRD occurrence between cases and controls in pre-weaned dairy calves.

Answer 24

 The BHB classification model had a 90 % sensitivity and 83 % specificity and the NEFA classification model achieved a sensitivity of 73 % and specificity of 74 %.  FTIR-based prediction models have potential as a screening tool for hyperketonemia and other metabolic disorders.  Combining prediction models for blood BHB, blood NEFA, and fat-protein ratio can improve identification of metabolically disordered cows

Answer 25

 Se and Sp of environmental sampling were 43.7 % (95 % BCI: 32.5−55.5) and 96.2 % (95 % BCI: 84.2−99.8), respectively.  Number of positive environmental samples increases with the within-herd prevalence  The probability of not observing a positive environmental sample decreased with the prevalence  Despite its imperfect accuracy, environmental sampling is an inexpensive and non-invasive sampling method to determine MAP infection status in tie-stall herds that can be used as a proxy to estimate the true within-herd prevalence.  The absence of positive environmental samples in a single sampling visit is likely an indicator of a very low within-herd prevalence rather than being MAP exempt.

Answer 26

 The number of stunning shots, meat pH, carcass bruises, severe hoof injuries, and liver condemnations, explained a significant variation in the incidence of various health and welfare consequences based on an animal’s origin, which confirmed their importance as ‘welfare iceberg’ indicators.

Answer 27

 Mechanistic epidemiological model produced based upon herds in western France  All females over two years old were tested. Based on the results, and taking into account the low test sensitivity, herds were annually assigned one of three statuses: A if the estimated true prevalence was below 7%, B if it ranged from 7 to 21 %, C otherwise.  Movement rewiring to prevent the sale of animals from high to low-prevalence herds reduces MAP regional spread  Improved hygiene and early culling of positive animals were relevant complementary on-farm control options to further decrease MAP spread  Culling infected cows early reduces the need for low-prevalence herds to purchase cows known as MAP-free. We showed that movement rewiring to prevent the sale of animals from high to low-prevalence herds reduces MAP regional spread. Targeting AAA herds made it possible to minimize the control effort to decrease MAP regional spread. However, animals purchased by AAA herds should have a moderate to high probability of being MAP-free, especially if the risk of purchasing animals from herds of unknown status cannot be managed. Improved hygiene and early culling of positive animals were relevant complementary on-farm control options to further decrease MAP spread. Future studies should identify how to define herd statuses to target optimal control measure combinations that could reduce the spread of MAP on a regional scale most effectively.

Answer 28

 Compared to the mean carcass weight for the non-infected culled cows, the carcass weight for High proviral load (H-PVL) culled cows was significantly decreased by 30.4 kg on average

Answer 29

 Herds located at a distance of >3 km from the roadworks were found to be at reduced risk of a bTB breakdown over the construction period compared with those situated within 1 km of the roadworks  Other previously reported risk factors such as inward movements, herd-size and herd-type were also associated with bTB risk in the final models  The potential for badger social group disturbance leading to the spatial spread of infection to cattle herds, as previously described in the United Kingdom, could be a hypothetical mechanism to explain these findings.

Answer 30

 The incidence risk at cow level (IRiC):  Was calculated monthly as the number of CM cases divided by the number of cows at risk in the population at the beginning of each month and then multiplied by 100. The at-risk period (denominator) for each cow started at the beginning of each month or date of calving within the month and ended at the end of the month, the day of CM, or exit from the study (e.g. culling, death, dry off)  assumes that the entire population at risk at the beginning of the study period remains at risk for the entire specified time period in terms of CM occurrence without accurately taking into account follow-up losses due to death or culling before the at-risk period is over  The incidence rate at cow level (IRaC)  Was calculated monthly as the number of CM cases divided by the number of cow-days at risk. The at-risk period for each cow started at the beginning of each month or date of calving and ended at the end of the month, the day of CM, or exit from the study (e.g. culling, death, dry off). Each cow that was present in any interval within these parameters contributed with the sum of days that each cow remained without CM and in the herd during a given month, considering the number of lactating cows at the beginning of the month and then multiplied by 10,000 cow-days.  The incidence rate at the quarter level (IRaQ)  Was calculated monthly as the number of CM quarters cases divided by the number of QDAR in each month and then multiplied by 10,000 quarters. The number of QDAR was calculated as the sum of days that each quarter remained without CM and in the herd during a given month, considering the number of lactating cows at the beginning of the month and assuming that all cows had four functional quarters. When calculating the incidence rate, an arbitrary multiplier of some power of 10 is generally used (Porta, 2014). The size of this 10,000 multiplier factor was chosen in order to have a final value that would be expressed as a whole number.  All lactating quarters were at risk for CM.  A quarter was at risk for a new CM case if there was at least 14 d between a previously diagnosed case and the current case in the same quarter, or if a different pathogen was isolated in the same quarter within 14 d The monthly incidence rate at the cow level was 16.6 cases per 10,000 cow-days, the monthly incidence rate at the quarter level was 4.4 cases per 10,000 QDAR and the monthly incidence risk at the cow level was 4.8 cases per 100 cows. Although the evaluation of QDAR requires additional computation when compared to other methods, it might allow for a more precise evaluation of the data and a more accurate evaluation of mastitis incidence. Clearly defining the methods used to report mastitis incidence will improve our ability to discuss and learn about the differences and similarities across studies, regions, and countries.

Answer 31

 Mean cumulative incidence for maximum mobility scores 2–5 SOM episodes were respectively 34, 16, 7 and 1 episodes per 100 cows per pasture period and 39, 19, 8, 1 episodes per 100 cows per housing period.  The mean total annual economic loss due to SOM resulting from the hoof disorders under study was €15,342: €122 per cow per year.  The major indirect losses at the herd level were due to additional indirect culling due to SOM (65%) and changes in the overall herd milk production (35%) because of additional younger replacement heifers entering the herd due to increased culling rates. This loss was composed of additional indirect culling due to SOM (∼65%) and changes in the overall herd milk production (∼35%) because of additional younger replacement heifers entering the herd due to increased culling rates. The bio-economic model presented novel results with respect to indirect economic losses arising due to SOM. The results can be used to stimulate farmer awareness and promote better SOM management.

Answer 32

 Over half of IR-only herds that went on to have a positive skin test result (a bTB herd ‘incident’) in 2020, had it triggered by at least one IR not clearing their 60-day retest, instead of by another test within the previous 15 months.  Severe-level reinterpretation of the high-risk IR-only disclosing tests identified in this dataset would turn 68 out of the 590 (12 %) IRs into reactors, generating 23 incidents, the majority (19 or 83 %) part of the 265 incidents that would have been declared at the retest. Classification tree analysis used to identify IR-only high-risk tests in herds eligible for severe interpretation would enhance the sensitivity of the test-and-slaughter regime, cornerstone of the bTB eradication programme in England, further mitigating the risk of disease spread posed by IRs.

Answer 33

 Strain-specific intervention strategies could improve the control and prevention of different S. aureus strains  The impact of many intervention strategies were strain-dependent.  Impact of changing mastitis intervention strategy depends on the dominant S. aureus strain in a herd.General Used for modelling based upon a general contagious pattern Contagious S. aureus genotype B (RS-PCR genotype) is contagious with a high within herd prevalence and associated with farms that have an S. aureus IMI problem. Van den Borne et al. (2017) determined that this strain had a higher transmission rate. Spill-over S. aureus genotype C (using RS-PCR) only causes IMI sporadically Leuenberger et al. (2019) also showed that genotype C often colonized body sites, other than the mammary gland, of cattle. The main reservoir for this strain appears to be non-mammary gland niches and, although contagious transmission of IMI to other mammary glands occurred, the main transmission is spill-over from those non-mammary gland niches to the mammary gland Clinical Specific S. aureus strains are associated with a higher odds to be isolated from clinical rather than from subclinical IMI Persistent Spa type t3401 is more persistent compared to other strains, although other strains associated with persistency also exist. A lower spontaneous recovery rate of this strain is associated with IMI persistance for a longer period.

Answer 34

 For calves, factors related to micro-climate were the main risk factors associated with AMU o These included: ventilation, minimum barn temperature, duration the barn was left empty between batches

Answer 35

 Nine variables appeared to be relevant predictors for the occurrence of Galba truncatula in both models.  These included reed/humid area, spring water, water bodies within a 100 m radius, and trees/bushes as powerful positive predictors.  High soil depth, temperatures frequently exceeding 30 °C in the year preceding the search for snails and temperatures below 0 °C especially in the second year before were identified to exert an adverse effect on the occurrence of Galba truncatula.  Reed, humid areas, spring water, water bodies and trees promote snail occurrence.  High soil depth and extreme temperatures compromise snail occurrence.  Temperatures measured near ground level proved to be more powerful predictors than macroclimatic parameters. Precipitation values seemed to be of minor impact in the given setting. Both regression models may be convenient for a fine-scale prediction of the occurrence of Galba truncatula, and thus provide useful approaches for the development of future spatial transmission models, mapping the risk of fasciolosis in Switzerland on farm-level.

Answer 36

 Animals with active fluke lesions (adult fluke seen on postmortem inspection) gained 17 (95 % CI 12–22) g/d less saleable beef than animals with no lesions and no visible fluke.  Animals with active fluke lesions were 11 (95 % CI 6.5–15) d older at slaughter weight than animals with no lesions.  Animals with historic lesions in which there was scarring of the liver but in which no adult fluke were seen showed a wide variation in effect estimates, consistent with some misclassification.  Meat from a herd with no fluke is associated with greenhouse gas emissions intensity approximately 1.5 % lower than the same herd with fluke.

Answer 37

 Testing of animals was considered important for BLV control, but the financial investment was prohibitive for farmers.  Test and cull as well as test and segregation approaches of test positive animals were considered efficient BLV control measures, but impractical and not feasible due to the supply managed Alberta dairy industry (i.e. milk is produced based on demand), with a high prevalence.  The management of test positive animals with BMP to prevent new infections and thereby decreasing the within-herd prevalence was considered the only realistic BLV control strategy.  Farmers indicated being inclined to implement BMP they considered feasible or that were considered a standard within the industry.

Answer 38

 Microsporidiosis, caused by the zoonotic eukaryote microsporidia spp. have serious health threat in high-risk groups, including immunocompromised individuals.  The estimated pooled prevalence of cattle microsporidiosis was 14 % (CI: 11.5–17 %) worldwide. Calves had the highest prevalence 20 % (CI: 14.8–26.5 %).  Enterocytozoon bieneusi with genotypes BEB4 (22 studies), J (21 studies), and I (17 studies) were the highest reported genotypes.  The present results highlight the role of cattle as reservoir hosts for human-infecting microsporidia.

Answer 39

 The model detected more infected herds than a single final test in 85 % of the scenarios which converged.  On average, around 20 %, for high test sensitivity scenarios, and 40 %, for low test sensitivity scenarios, of infected herds that were undetected by the test were accurately classified as infected by the model.  Detection of additional newly infected herds was always associated with an increased number of false positive herds (except for one scenario).

Answer 40

Our final model retained: * (herd size) (Odds Ratio (95% CI): 1.72 (1.40, 2.12)), * distance from test positive herds (0.54 (0.44, 0.66) for each extra land-parcel boundary crossed to reach the closest herd which tested positive the preceding year), * (potential trojan dams + 1) (1.29 (1.05, 1.60)). The same variables were retained in the model where herds with confirmed transient infections only (n = 25) were excluded. Conclusions * Our findings suggest that care with biosecurity at farm boundaries and visitors and equipment entering the farm, and avoidance or careful risk assessment of purchasing potentially pregnant animals, may help prevent introduction of BVDV to low-risk herds. * At policy level, consideration of herd size, proximity to test positive herds and purchasing patterns of potentially pregnant cattle may help target surveillance measures towards the end of the eradication programme.

Answer 41

* The FMD outbreaks started during the month of January, culminated in February and stopped during the month of April 2019. * The most common serotype was O (45.83%), followed by Asia1 (29.17%) and A (13.89%); however, some case farms had mixed infection with serotypes A and O (9.72%) and serotypes O and Asia1 (1.39%). * Multivariable analysis revealed that the history of 1. introducing a new animal with unknown FMD vaccination status in the herd (OR =11.51, 95% CI = 3.28 – 40.47), 2. not practicing regular vaccination against FMD (OR = 20.81, 95% CI = 4.59 – 94.35), 3. history of the visit of an animal broker (OR = 9.06, 95% CI = 2.31 – 35.61), 4. distance of the farm to a nearby livestock farm (OR = 6.13, 95% CI = 1.39 – 27.01) and large herd size (OR = 20.79, 95% CI = 2.45 – 176.27) * were significantly associated with the occurrence of FMD outbreaks in Punjab province during 2019.

Answer 42

Conclusions: Australian dairy veterinarians are generally aware of the risk of resistance to antimicrobials and the need for stewardship, with clinical factors having the most impact on antimicrobial prescription. However, non-clinical factors incorporating awareness of guidelines and their attitudes on antimicrobial resistance risk and prescription concerns impact on the choice and prescription of antimicrobials. Implications: The development of prescription policy and guidelines, alongside effective communicative extension programs to increase veterinarian uptake, provides an avenue to mitigate AMR risk in Australian dairy cattle.

Answer 43

* Breed, birth weight, age at transport, body weight immediately before transport, and transport duration were associated with body weight at arrival. * Holstein calves had greater body weights at arrival compared to Holstein-beef calves. * Calves with greater birth weights and greater body weights immediately before transport had greater body weights at arrival. * Calves over 5 d of age at transport had greater body weights at arrival compared to calves transported at 5 d of age or less. * Calves transported for 6 h had a greater body weight at arrival compared to 12 h or 16 h, and those transported for 12 h had a greater body weight at arrival compared to 16 h.

Answer 44

* The pooled N. caninum seroprevalence in cattle was estimated to be 12.2%. The highest seroprevalence of N. caninum infection in cattle was in Southern China (20.9%), while the lowest seroprevalence was in Northwest China (9.4%). * The seroprevalence of N. caninum in the sub-group 2016 or later (10.2%) was lower than that in 2012-2015 (20.7%) and before 2012 (17.2%). * Yaks were the least infected species of cattle (7.3%; Yellow cattle 18.1%; Buffalo 7.8%; Dairy cattle 21.5%). * Cattle aged > 5 years had higher seroprevalence (20.7%) than that aged 3-5 years (10.7%) and < 3 years (14.2%). * In season subgroups, the lowest N. caninum seroprevalence was found in summer (21.3%). * Free ranging cattle had a 27.2% seroprevalence of N. caninum, which was higher than 7.8% in stall-feed cattle. * The seroprevalence of N. caninum in female (22.6%) cattle was higher than in males (13.4%). Meanwhile, the prevalence was higher as increased parity and abortion. * The results indicated that N. caninum infection in cattle was widely distributed in China.

Answer 45

* The diseases and conditions modelled resulted in total adjusted losses of £ 404/cow/year, equivalent to herd-level losses of £ 60,000/year. * Unadjusted aggregation methods suggested losses 14–61% greater. * Lameness was identified as the costliest condition (28% of total losses). * Variations in the prevalence of fasciolosis, neosporosis, and paratuberculosis (only a combined 22% of total losses) were nearly as impactful individually as variations in the prevalence of lameness. * Conclusion: the costliness of a disease may not always be the best indicator of the investment its control warrants; the costliness rankings varied across approaches and total losses were found to be surprisingly sensitive to variations in the prevalence of relatively uncostly diseases.

Answer 46

* Considering detection methods, the pooled prevalence was estimated to be 24% (95% confidence interval (CI), 19–30%) using copro-antigen techniques, 22% (95% CI, 17–28%) using molecular, and 16% (95% CI, 12–20%) using microscopic detection. * Molecular methods showed that the highest number of reports were associated with assemblage E (45/46; 97.83% studies), assemblage A (33/46; 71.74% studies) and assemblage A+E (10/46; 21.74% studies). * The pooled prevalence different of subgroups (WHO regions, countries, and type of cattle) were analyzed separately. Moreover, a significant association was observed between G. duodenalis infection with cattle suffering from diarrhea (odds ratio (OR), 2.61; 95% CI, 1.50–4.55) and pre-weaned calves (OR, 1.79; 95% CI, 1.08–2.95). * Conclusion: the corresponding control scheme and effective management measures should be formulated to reduce the transmission of G. duodenalis infection according to the difference of geographical conditions in different areas.

Answer 47

* The highest seroprevalence of Brucella infection was reported among animals raised in herd size > 100 animals (65.5%), with no disinfection post-calving (61.7%), with a history of abortion (59.6%), and with shared equipment without thorough cleaning and disinfection (57.1%). * The multiple stepwise logistic regression modeling identified herd size, history of abortion, and disinfection post-calving as important risk factors. * CART modeling identified herd size, disinfection post-calving, history of abortion, and shared equipment as the most potential risk factors for Brucella infection. * Comparing the two models, CART model showed a higher area under the receiver operating characteristic curve (AUROC = 0.98; 95% CI 0.95 – 1.00) than the binary logistic regression (AUROC = 0.89; 95% CI 0.73 – 0.92). * Conclusion: Brucella infection is most likely to spread among animals raised in large herds (>100 animals) with a history of abortions and bad hygienic measures post-calving.

Answer 48

* Conclusion: three decision strategies (genomic selection for NM$, selective therapy for PS-CM, and selective dry cow therapy for PS-CM prevention) when combined can reduce the incidence of PS-CM and the associated ABU, while increasing the profitability of the herd.

Answer 49

* Farmers were more likely to rank the impact of pinkeye on farm productivity as high if they had younger cattle, treated cattle with pinkeye more frequently, and as their herd size increased. Fewer farmers chose pinkeye as an animal welfare concern than as an economic and farm management issue, but overall animal welfare was rated by the greatest number of farmers as a high severity concern (n = 691), followed by decreased sale value and farm profits (n = 561). * The median amount reportedly spent on pinkeye in 2018 by Australian farmers (n = 779) was $250.00 per farm. Farmers reported spending more money on pinkeye as herd size and number of cattle affected by pinkeye increased, their perception of pinkeye impact on farm productivity and animal welfare increased, if they treated pinkeye more frequently, reported higher fly worry, if their herds contained Angus cattle, if they bred on farm, and if they were located in southern Australian regions.

Answer 50

* On day 42, calves of the dams vaccinated simultaneously had higher neutralizing antibody titers against three serotypes than the calves of only FMD vaccinated dams. * IgG1/IgG2 ratio was higher in single-dose groups than booster-dose groups against serotype A in calves. * A positive correlation was found in the transmission of maternal antibodies from mothers to calves in simultaneous administration groups. * Conclusion: FMD and E. coli vaccines can be simultaneously applied to dams in the 7th and 8th months of gestation.

Answer 51

* The proportion of lame cows was positively associated with a previous housing period of four months or more compared to three months, all cubicles being outside recommended lengths and repairing roadways every two to three years compared to either yearly or more than every four years to never. * The proportion of cows below minimum target grazing body condition score of 2.75 was negatively associated with participation in elective herd disease-testing in the past year. * The proportion of cows with tail lacerations was positively associated with using a single breeding method, not employing part-time staff and not using brisket boards in cubicles. * Previous housing period length was significantly associated with the proportion of cows with integument damage, although the direction of association was unclear. * Moderate to severe nasal discharge was positively associated with collecting yard holding times of ≤ 60 min compared to > 90 min. * Ocular discharge was negatively associated with manual health record-keeping and a collecting yard below the recommended area of 1.4 m2/cow. * The proportion of cows with an avoidance response distance > 1 m was positively associated with herding cows without a dog present and having no additional full-time staff. * Multiple risk factors were related to the housing period, suggesting that potential carry-over effects of housing management on welfare persist into the grazing period

Answer 52

We additionally evaluated the sensitivity of the parameter estimates and predicted probabilities of freedom to the prior distributions for the different model parameters. First, default priors were used in the model to enable comparison of model outputs between study regions. Thereafter, country-specific priors based on expert opinion or historical data were used in the model, to study the influence of the priors on the results and to obtain country-specific estimates. * For dairy herds that were considered free from infection within their own control programme, the predicted probabilities of freedom were very high for all study regions ranging from 0.98 to 1.00, regardless of the use of default or country-specific priors. * The priors did have more influence on two of the model parameters, herd-level sensitivity and the probability of remaining infected, due to the low prevalence and incidence of BVDV in the study regions. * The advantage of STOC free model compared to scenario tree modelling, the reference method, is that actual data from the CP can be used and estimates are easily updated when new data becomes available.

Answer 53

* Practices which were found to be of importance with respect to Enterococcus spp. included management of slurry, external entry of livestock to the dairy herd, use of bedding materials and conditioners, cubicle cleaning routines and antibiotic practices, including use of β-lactams and fluoroquinolones. * Practices deemed to be of importance for E. coli MICs included cubicle and bedding management practices, teat preparation routines at milking and the milking procedure itself. * Conclusion: a variety of routine farm management practices are associated with MICs of sentinel bacteria in bulk milk.

Answer 54

* We sought to determine whether the system based on routinely collected milk recording and meteorological data would have detected the 2012 Schmallenberg virus (SBV) incursion into Ireland earlier than conventional surveillance methods. * Using a range of thresholds, our model generated alarms throughout September 2012, between 4 and 6 weeks prior to the first laboratory confirmation of SBV in Ireland. * This system for monitoring milk yield represents both a potentially useful tool for early detection of disease, and a valuable foundation for developing similar tools using other metrics.

Answer 55

* No evidence of any significant effects of MI training on the eight performance variables analyzed. * A pattern of numerically higher values (better performance) in trained veterinarians with poor or moderate MI skills than in untrained veterinarians was observed in most variables. * Clients were highly satisfied with veterinarians’ attitude, competence and time efficiency. Farms implemented a median of 66.7% (interquartile range: 50–100) of the measures partially or fully. * Veterinarians allocated little time to VHHM visits (median: 2.2; interquartile range: 0.65–4.1 h per week of full-time work within cattle). * Veterinarians with moderate skills spent 2.14 times more time on VHHM visits than untrained veterinarians, but the confidence interval was wide (0.88–5.21). * The pattern of numerically higher values in trained veterinarians supported findings from other studies in the same project indicating a positive effect of MI training on VHHM. Our observations suggest a considerable potential to increase veterinarians' engagement in VHHM.

Answer 56

* A cut-off of 135 AU was estimated to be optimal using Bayesian latent class analysis with three tests in multiple populations, accounting for conditional dependence between tests. * At this cut-off, the DSe and DSp of the MilA ELISA were estimated to be 92.1 % (95 % highest probability density [HPD] interval: 87.4, 95.8) and 95.5 % (95 % HPD: 92.4, 97.8), respectively. * The DSes of the BIO K260 and BIO K302 ELISAs were estimated to be 60.5 % (95 % HPD: 54.0, 66.9) and 44.6 % (95 % HPD: 38.7, 50.7), respectively. * DSps were 95.6 % (95 % HPD: 92.9, 97.7) and 97.8 % (95 % HPD: 95.9, 99.0), respectively. * Mycoplasma bovis seroprevalence was remarkably high at follow-up after 42 days on the feedlots. * Conclusion: MilA ELISA has higher DSe than the BIO K260 and BIO K302 assays

Answer 57

* The present work found that most (84 %) farmers felt they lacked understanding of copper related problems and their associated terminology. * However, farmers who felt they had the least knowledge appeared more likely to underestimate their knowledge, and those who felt more confident in their knowledge were more likely to be overestimating it. * Simple over- and under-supply of copper were only recognised by a small proportion (17 %) as causes of copper related problems while more complex issues were better recognised (27 %) as potential causal factors. * However, the more specific terminology relating to the molybdenum-sulphur antagonism was poorly understood by most respondents (96 %).

Answer 58

* By extrapolating our results obtained from using data from dairies enrolled in the DHIA testing program for the western US, we demonstrated that regardless of the criteria used to classify cows as high risk of IMI at dry-off (scenarios 1–5), if selective dry cow therapy is adopted in the US, the dairy industry could reduce the use of antimicrobials around the dry-off between 31 % and 66 %. * Multiparous cows had greater odds of being classified as high-risk than primiparous cows. * Cows dried off in the spring, summer, and fall had lower odds of being classified as high-risk compared to cows dried off in the winter. * Advanced days in milk at dry-off was associated with greater risk of IMI at dry-off. * Greater milk yield and higher protein percentage at the last test-day before dry-off were associated with decreased odds of a cow being classified as high-risk at dry-off * cows in small herds had greater odds of being classified as high-risk at dry-off

Answer 59

* Using the beta-regression model, compared to Canada, non-selective ESC-R Salmonella enterica was less likely isolated from food producing animals in other eight countries (Odds ratio range: 0.07-0.76). We observed an interaction between the country and the year with a significantly decreased proportion (P < 0.05) of non-selective ESC-R Escherichia coli from the Netherlands, the United Kingdom, and the United States compared to Canada over the years. * There was a linear correlation between non-selective ESC-R Escherichia coli and ESC use from Netherlands (Spearman's ρ = 0.91, P < 0.0001). * For the six European countries, the interaction between the country and year showed a significant decrease in the proportion of selective ESC-R Escherichia coli over the years for the Netherlands compared to Denmark (P = 0.002). * This study reveals variability in the recovery of ESC-resistant bacteria among the countries that seems likely influenced by the individual country policy on the use of critically important antimicrobials and resistance surveillance programs. * However, there is a need for harmonization and consistency in food animal sources of bacterial isolates used in surveillance programs within and between the countries for easy comparability.

Answer 60

* At cut-off PP % ≥ 15 for a Bmilk ELISA, which is used by provincial authorities, the herd prevalence of S. Dublin estimated using informative prior was 6.8 % (4.3-9.9) in population 1. The herd sensitivity and specificity estimates (95 % Bayesian Credibility Intervals) for Bmilk ELISA were 40.6 % (15.6-88.8) and 91.9 % (88.3-95.8), respectively. * Positive and negative predictive values of Bmilk ELISA were 26.4 % (8.5-60.2) and 95.8 % (92.1-99.2), respectively. * Increasing Bmilk ELISA cut-offs had little influence on predictive values. * Our study shows that a test-positive herd based on a single bulk milk sample would require complementary tests for status confirmation. However, a test-negative herd could be classified as true negative with a high certainty

Answer 61

* After experimental challenge, 6 of 14 (43 %) control animals aborted at a higher rate (P < 0.05) when compared to RB51 vaccinates in years 4 and 5, but not year 6 (0 %, 10 %, and 50 %, respectively). * When comparing recovery of Brucella from all tissues except head lymph nodes draining the site of challenge, RB51 vaccinates had reduced infection rates (P < 0.05) after experimental challenge at 4 years (14 %), but not at 5 or 6 years (78 % and 67 %, respectively) when compared to non-vaccinated cattle (93 %). * Our data suggests that calfhood vaccination with RB51 does not induce lifelong immunity and suggests implementation of booster vaccination by 4–5 years of age should be utilized in endemic areas to maintain high levels of protection.

Answer 62

* Sixty-eight percent (419 animals) of the overall sample of calves received at least one individual antimicrobial treatment due to a disease event during the fattening, and 280 of these (45 % of the overall sample) had more than one treatment. * On average, the net carcass weight of calves individually treated more than once was about 10 kg lower than that of untreated calves or treated only once. * Moreover, the carcasses of calves that received more than one treatment were 16 times more at risk of being severely penalized in payment at the slaughterhouse due to a net weight below 110 kg than those of untreated calves. * Serum analysis data of a subsample of 105 calves belonging to 3 out of the 6 batches collected within 5 days after their arrival to the veal farm identified 3 persistently infected animals by bovine viral diarrhea (BVD) virus and a prevalence of calves with serum immunoglobulin concentration below 7.5 g/L of 37 %. * The presence of specific antibodies against infectious bovine rhinotracheitis (IBR) and bovine respiratory syncytial virus (BRSV) and a serum immunoglobulin level above 7.5 g/L at the onset of the fattening were the most important factors associated with a decreased risk of multiple individual antimicrobial treatments (and thus, disease development) or with a delay in disease onset during the fattening, thus leading to better performances at the slaughter. * The outcomes of this study suggested that a relationship could exist between calf serostatus upon arrival to the veal farm and the possibility to avoid multiple individual antimicrobial treatments during fattening.

Answer 63

* The Bland- Altman plot comparing the RID and CE methods, revealed that the serum IgG concentrations obtained by RID were on average 2.25 (95 % CI 1.62–2.88) g/L higher than those measured by CE. Optimal cut-off values for CE, corresponding to the FPT values as measured by RID of 10, 18, and 25 g IgG/L serum, were respectively 10, 15, and 20 g IgG/L. The overall diagnostic accuracy of the three diagnostic tests was comparable at the FPT cut-off point of 10 g IgG/L serum (i.e. 85 %). At higher cut-off points for FPT, the RID and CE assays presumably performed better that the Bx method. * In conclusion, we demonstrated that: (1) the CE method is a good alternative for the RID assay, the latter having important constraints when considering its practicality, and (2) the Bx method is a cheap and user-friendly indirect method to evaluate the FPT in new-born Belgian Blue beef calves.

Answer 64

* There was a significant negative correlation between the ’Hygiene score’ and the apparent MAP seropositivity of the given farm. * Taking the calf away immediately after birth was associated with an average 55 % decrease in the odds of seropositivity as compared to the longer time spent with the dam. * Discarding of colostrum from previously PTB+ cows after calving was associated with a 48 % decrease in the odds of seropositivity as compared to farms where the colostrum or milk of PTB+ cows was not discarded but fed to the calves. Key findings * In conclusion, calf management is key in controlling paratuberculosis where immediate removal of the calf from its mother and the feeding of MAP-free colostrum and milk are essential elements.

Answer 65

* During the 0–30-day period, the calf mortality risk was associated with dam parity, calving status, gestation length, sex, birth season and twin births (P < 0.05), but not with the number of inseminations to conception. Low parity, dystocia, gestation lengths < 280 days and > 301 days, male calves, calves born in autumn and winter and twin births yielded higher CMRs. * Low dam parity also yielded higher CMRs during the 31–60-day, 61–90-day and 91–120- day periods (P < 0.05), but no other factors were associated with the CMR during these periods. Thus, various cow and calf factors were shown to be associated with CMRs in Japanese Black calves, and calves with these factors should be considered high-risk calves.

Answer 66

 In conclusion, a milk ELISA for bTB antibodies, especially bulk tank milk antibodies, could be used as an efficient tool for rapid screening in surveillance, which might be followed by confirmatory testing with IFN-γ assay in dairy cattle, during the implementation of bTB control programmes.  Relevant milk factors should be considered to adjust the S/P% with the aim of classifying the infection status of animals and herds as accurately as possible.

Answer 67

 At validation, the sensitivity (Se) of the iELISAINTA in bulk milk samples was 98.61 %, and the specificity (Sp) 98.79 % with a ≥ 10 % of positivity (PP) cutoff. In individual milk samples, the Se was 98.04 %, and the Sp 98.56 % with a ≥ 16 PP cutoff. The developed iELISAINTA showed a very good performance and it could be used as a screening assay for anti-B. abortus antibodies detection in individual milk samples and for epidemiologic surveillance in bulk milk samples

Answer 68

 Analyses identified two risk factors for body condition < 3.0 and four for body condition > 3.5, the target range during the housing period.  Four risk factors were identified for each of ocular discharge, nasal discharge and avoidance response of > 1 m from human approach.  Six risk factors each were associated with the proportion of lame cows and integument damage to the head-neck-back or hindquarter regions.  The greatest number of risk factors, 12, were associated with tail injury (broken, lacerated or incomplete tails).  Risk factors associated with multiple indicators of welfare were cow comfort index (tail lacerations and hindquarter integument damage), cubicle width (broken and incomplete tails), shed floor slipperiness (lameness and head-neck-back integument damage), shed light-level (tail lacerations, avoidance response and below target body condition), shed passage width (broken tails and head-neck-back integument damage) and presence (incomplete tails) or absence (broken tails) of a collecting yard backing gate.  With the large number of risk factors associated with tail injury, continued research is necessary to identify causes and determine prevention methods to contribute to improved overall welfare of dairy cows.  Housing features meeting recommended guidelines from the literature were frequently associated with greater negative indicators of welfare.  In light of this, housing guidelines may benefit from regular re-evaluation to ensure facilities meet the welfare needs of cows during the housing period.

Answer 69

 Classifying herds according to the Danish eradication scheme classification gave an apparent prevalence of 38% (95% confidence intervals 34–43%) and an estimated true prevalence of 40% (95% confidence intervals 35–45%), taking into account the test sensitivity and specificity.  Of the 401 herds which completed the quarterly bulk tank testing, 45% had one or more positive bulk tank results

Answer 70

 Specifically, the limit of detection was approximately 100 CFU/g or even less if binomial approaches were used for the determination of the 95 % probability of detection (logit and clog-log models) with sufficient repeatability and reproducibility.  Our validation study underlines the good performance of this IS900-qPCR assay for diagnosis of MAP representing a valid and robust alternative to culture.  Moreover, coupled with the semiautomatic magnetic beads DNA extraction method, this assay allows the rapid processing of numerous samples.

Answer 71

 This study suggests that milk production losses due to severe lameness of dairy cows might be higher in AMS herds compared with cows in herds with a conventional milking system, a likely result of a reduced milking frequency of those cows. Prevention of severe lameness may be more cost-effective in AMS herds than in herds with a conventional milking system.

Answer 72

 the primary exposure was the test status following a reactor retest classified as mutually exclusive categories based on bovine and avian tuberculin reactions: o standard interpretation inconclusive (Sdi), o severe interpretation inconclusive (Svi), o single intradermal test (SIT) reactors (SITr), o SIT inconclusive (SITi), o avian tuberculin reactors (Ar), and test negative animals.  Results: o Sdi 12.242 (95 %CIs: 5.236–28.625; p < 0.001), o Svi 4.101 (95 %CIs: 3.423–4.913; p < 0.001), o SITr 2.503 (95 %CIs: 1.878–3.338; p < 0.001), o SITi 1.741 (95 %CIs: 1.195–2.538; p = 0.004) and o Ar 1.065 (95 %CIs: 0.833–1.361; p = 0.616) were associated with the following odds ratios, for failing the next test, respectively. o Other factors that were associated with increasing risk included age (older cohorts were at greater risk than the youngest cohort), breakdown history of the herd (greater number of breakdowns prior to the study period), and the time between exposure test and outcome test.  These results provide further evidence to inform risk-based management policies for TB, including the removal of Sdi animals in higher risk situations.  The results characterise the future animal-level risk posed by Svi animal and suggest this risk may require policy led interventions.

Answer 73

 Enterocytozoon bieneusi (E. bieneusi) is an important zoonotic microsporidian pathogen that has a variety of hosts. Cattle are reservoir hosts of E. bieneusi, and play an important role in the epidemiology of E. bieneusi.  An overall E. bieneusi prevalence (95% CI) in cattle was 12.9% (2566/19,791, 9.0–14.6%).  The highest prevalence of E. bieneusi was 17.3% (13.9–20.3) in South America, and the lowest was 6.5% (4.1 – 9.4) in Africa 6.5%.  The prevalence of E. bieneusi after 2016 (11.1%) was lower than 2016 and before (12.3%).  Cattle aged 3–12 months had a higher prevalence (14.8%) as compared with cattle aged > 12 months (8.2%).  The combined prevalence of E. bieneusi in the dairy cattle was 14.4%, which was higher than that in other species.  In the subgroup of season, E. bieneusi prevalence in cattle was higher in spring (17.4%) and autumn (19.7%) than in summer (8.5%) and winter (8.5%).  E. bieneusi prevalence in naturally grazed cattle was 3.6% and 13.7% in intensively fed cattle.  A total of 83 E. bieneusi genotypes were prevalent in cattle, of which 15 genotypes found in the cattle had previously been found in humans.  These data indicated that E. bieneusi was ubiquitous in cattle worldwide and carried a potential risk of infection in humans. Thus, the farm managers should provide a scientific mix of nutrients to improve cattle immunity, keep the environment clean, and disinfect regularly.

Answer 74

 Risk-based trading effectively reduced the increase in herd prevalence over a 10-year-period in Ireland: from 50% without risk-based trading to 42% with risk-based trading in the metapopulation only, and 26% when external purchases were risk-based as well. However, for risk-based trading to be effective, a high percentage of dairy herds had to participate.  The most important within-herd measures were improved herd hygiene and early culling of highly infectious cows. These measures reduced both herd and within-herd prevalence compared to the reference scenario. Combining risk-based trading with within-herd measures reduced within-herd prevalence even more effectively.

Answer 75

- Optimal thresholds were determined as < 7.9, < 8.3, < 8.7, < 9.4% for the BRIX-REF, and < 4.6, < 5.2, < 5.4, < 5.8 g/dL for the STP-REF in estimating IgG concentrations of < 10, < 18, < 25, < 32 g/L, respectively. - Se and Sp of BRIX-REF were 88.8% and 89.1% for < 7.9% Brix, 81.6% and 94.2% for < 8.3% Brix, 77.9% and 97.4% for < 8.7% Brix and 81.7% and 91.2% for < 9.4% Brix, respectively. - Se and Sp of STP-REF 92.5% and 88.2% for < 4.6 g/dL; 92.1% and 87.1% for < 5.2 g/dL; 81.7% and 93.6% for < 5.4 g/dL; 79.0% and 94.1% for < 5.8 g/dL, respectively. - Both, digital Brix and STP refractometers performed well to estimate the status of passive immunity in dairy Simmental calves.

Answer 76

* This research identified five subcategories (cowtypes) of metabolic responses in transition dairy cows: Healthy, Athlete, Clever, Hyperketonemia, and Poor Metabolic Adaptation Syndrome (PMAS)4. * The objective of this study is to evaluate the association of the cowtypes with the disease-free survival time in dairy cows during early post calving using an accelerated failure time regression model. * Using Healthy cowtype as reference level, Athlete, Clever, and PMAS cowtypes were found to be significant for the disease-free survival probability (P < 0.01). Conversely, Hyperketonemia cowtype was not significant (P = 0.182). Compared to the Healthy cowtype, all other cowtypes had a negative effect on the survival probabilities, which was higher for PMAS cows. * The results showed 0.091 (95% CI:0.089,0.092), 0.077 (95 % CI:0.074,0.078), 0.684 (95 % CI:0.067,0.069), 0.138 (95 % CI:0.136,0.139), and 0.009 (95% CI:0.008,0.010) of probability of being in Healthy (9.1%), Athlete (7.7%), Clever (68.4%), Hyperketonemia (13.8%), and PMAS (0.9%) cowtype, respectively. * These estimates represent the proportion of cows belonging to the different cowtypes in a herd; information which may prove useful for herd management. The application of blood biomarker predictions using milk FTIR allows us to investigate differences between predicted cowtype and movements between these states and the association with time to disease.

Answer 77

* Belonging to the group of herds with a high longevity was associated with lower calf- and cow mortality, a higher percentage of cows with a high somatic cell count (HSCC), fewer inseminations per pregnancy for heifers and more inseminations for cows, a higher antibiotic use in adult dairy cows and a lower antibiotic use in calves compared to the average Dutch dairy herd. Further analysis showed that the higher percentage of cows with a HSCC could be explained by the higher share of older cows. * Herds with a low longevity had a higher calf- and cow mortality, a lower percentage of cows with a HSCC, more inseminations for heifers and fewer for cows, lower antibiotic use in cows and higher antibiotic use in calves compared to the average Dutch dairy herd. * To conclude, there were differences in cattle health between groups of herds with a different longevity.

Answer 78

* The model results indicated median total costs of mastitis of € 230 per generic IMI case (i.e., a weighted average of all pathogens). * The most substantial cost factors were the extra mastitis cases due to transmission, culling, and milk production losses. * Other significant costs originated from dry cow treatments and diverted milk. * The model also indicated median total costs due to chronic mastitis of € 118 (51 % of the total mastitis costs). The share of chronic mastitis relative to the total mastitis costs was substantial. * Transmission of contagious bacteria had the largest share among the chronic mastitis costs (51 % of the costs of chronic cases). * The large share of chronic mastitis costs in the total mastitis costs indicates the economic importance of these mastitis cases.

Answer 79

* The MCDA found that biosecurity combinations that included “double-fencing farm boundaries” used in conjunction with “vaccination against BVDV” were most appropriate for management of BVDV in an initially naïve, self-replacing seasonal single-calving beef herd over a 15-year period.

Answer 80

* The incidence of pinkeye was not significantly different between vaccinated and control groups, both alone (p = 0.67) and after adjusting for sex and weight differences (p = 0.69). * The vaccine was not protective against naturally occurring pinkeye under the field conditions.

Answer 81

* The model achieved an average area under the ROC curve of 0.73 on unseen test data. * Using feature importance analysis, we identified a number of features that have a high discriminatory value for calving difficulty, including maternal and paternal breeding values, and past phenotypic measurements of the cow

Answer 82

* Restricting the ICC counts to herds which had previously or would in the future test positive for bTB resulted in improved model fits, but this was not the case if only the previous test status was considered. This suggests that in many cases bTB infected animals are moving out of herds before being identified through testing, and that risk-based trading approaches should not rely solely on the previous test history of source herds as a proxy for future risk. * Model fit was also improved by the inclusion of variables measuring bTB history of the herd, bTB in neighbouring herds, herd size, herd type, the movement network measures “in strength” and “betweenness”, altitude, modelled badger abundance and county. * Rainfall was not a good predictor. * The most influential measures of bTB in nearby herds (a proxy for neighbourhood infection) were the proportion of herds with a history of bTB whose centroids were within 6 km, or whose boundaries were within 4 km, of the index herd

Answer 83

* The index combined spatial models of land use distribution (the probable distribution defining animal use of space) based on pasture location for cattle, and based on land cover for badgers, with proxies for animal density for both species. * We observed high values of BACACIX from the southwest to the northeast of France and from Brittany to the Channel coast. Conversely, in two areas (north-central area and Mediterranean coast), index values were low, suggesting that indirect cattle–badger contacts were unlikely. * A logistic regression model showed that after controlling bTB over the previous decade, the value of the index was positively associated with the risk of cattle outbreaks between 2001 and 2010 (OR = 1.57). * In addition, the risk of bTB occurrence in cattle decreased when the pasture area outside the badger space use distribution increased. In the future, the spatial index of indirect cattle-badger contacts we propose could help to better target bTB surveillance and control in France.

Answer 84

* Testing, movement restrictions and output losses account for over three quarters of total uncompensated costs. * Total costs rise with herd size and duration of controls. * The composition of consequential costs changes as total costs increase, with an increasing proportion of the costs being associated with output losses and movement restrictions, and a decreasing proportion of costs associated with testing costs. * Costs tend to be higher for dairy than beef herds but this is likely due to larger herd sizes for dairy. * Overall we find the total farm costs of bTB surpass those compensated for by Government in Great Britain. This study contributes to the public-private cost-sharing debate as farmers bear some of the economic burden of a disease breakdown.

Answer 85

* A producer survey revealed that more than 50% of the study herds relied on live animal markets as a source for replacements and reported more FMD outbreaks (P-value=0.09), FMD herd morbidity > 50% (p-value=0.05), and weight loss > 15 kg/animal in FMD clinical cases (P-value=0.01) in comparison to herds that received replacements from other farms, imported, or purchased from small stakeholders. * More than 70% of the surveyed farms received replacements ≤ 1year old and reported significantly higher FMD outbreaks (P-value=0.02) in comparison to farms that received older animals. * More than 80% of the surveyed farms performed physical examination of newly purchased animals before arrival at their premises. Of the surveyed farms, 73% reported FMD outbreaks with 67% of the outbreaks being reported during the Fall and Winter seasons. * The decision tree identified physical examination of newly purchased animals prior to arrival and mixing with a premises beef herd followed by vaccination against FMD upon arrival as the intervention resulting in the lowest probability of FMD outbreak (8.9%). * In contrast, herds that did not perform physical examination and delay the FMD vaccination for two or more weeks had the highest probability of FMD outbreaks (33.5%).

Answer 86

* The median annual group-specific hormone use was o PGF2α: 21.3 (mean=26.1; min 0.0; max=180.0), doses per 100 adult dairy cows o GnRH: 11.0 (mean=15.3; min=0.0; max=127.0) doses per 100 adult dairy cows o Progesterone: 0.0 (mean=1.8; min=0.0; max=40.3) doses per 100 adult dairy cows. * High user herds had a calving interval and a calving-to-1st insemination interval that was 9.3 ± 2.6 and 16.4 ± 2.1 days shorter than that of non-user herds (424.0 ± 2.7 and 114.0 ± 2.1 days), respectively. Furthermore, high-user herds needed on average 0.3 ± 0.04 inseminations more to get their cows pregnant compared to non-user herds (1.83 ± 0.04 no. of inseminations per cow). * Medium-user herds had a 6.5 ± 2.6 days shorter calving interval and a 12.0 ± 2.1 days shorter calving-to-1st insemination interval with 0.2 ± 0.04 additional inseminations per cow compared to non-user herds. * Low-user herds had a 6.2 ± 2.7 days shorter calving interval and a 7.9 ± 2.2 days shorter calving-to-1st insemination interval compared to non-user herds. * The model produced the same trend for prostaglandin and GnRH use, with the higher use being associated with a shorter calving interval, a shorter calving-to-1st insemination interval, and a higher insemination per cow number. * For progesterone use the opposite effect was observed. * In conclusion, using a large representative herd-level dataset, hormone use was associated with a better reproductive performance in terms of calving interval and calving-to-1st insemination interval but gave extra average number of inseminations per cow. It should be monitored how reproduction performance changes when striving for a more prudent hormone use.