The veterinary journal Flashcards
Meta-analysis of the effects of essential oil as an alternative to monensin in diets for beef cattle
Torres et al., 2021
- The substitution of EO for monensin did not affect methane production, ruminal pH values, average daily gain, feed efficiency or carcass weight.
- EO increased carcass dressing percentage (WMD = 0.38%; P = 0.03), ribeye area (WMD = 0.82 cm2; P < 0.0001) and subcutaneous fat thickness (WMD = 0.56 mm; P < 0.0001) values increased.
- Although the use of EO instead of monensin had no influence on the performance of beef cattle fed high-grain diets, the prevalence of hepatic abscesses increased 84.9% and the replacement of monensin by EO increased the risk ratio of hepatic abscess prevalence by 107% (likely associated with the ability of monesin to reduce risk of liver abscess, rather than EO causing abscesses).
- Therefore, the use of EO in high-grain beef cattle diets was ineffective in protecting the liver against abscesses.
The regression of the bovine tuberculin reaction: Results from the Reactor Quality Assurance study in Northern Ireland
Courcier et al., 2021
- A proportional decline in the bovine tuberculin reaction occurred over time
- Follow-up measurement of tuberculin reactions and the serial use of the IFN-γ assay in large breakdowns has the potential to provide both a mechanism for quality assurance of the current CICT bTB surveillance and the identification of atypical breakdowns or reactors
A multidisciplinary approach to reduce and refine antimicrobial drugs use for diarrhoea in dairy calves
Gomez et al., 2021
- The intervention consisted of modification of management practices for disease prevention, health evaluation training of farm staff, implementation of an algorithm directed at antimicrobial therapy for diarrhoeic calves, and monthly farm visits.
- Data was collected and evaluated before intervention (BP) and after intervention (AP)
- Reduced antimicrobial treatment rates occurred on seven farms (P < 0.01), but not on three farms AP.
- A total of 85% (1303/1573) and 18% (310/1698) of diarrhoeic calves were treated with antimicrobial drugs in the BP and AP (P < 0.001), respectively.
- There were no differences in the incidence of diarrhoea or mortality between periods.
- In the AP, the use sulfamethazine and trimethoprim decreased on eight farms, one farm discontinued use of lincomycin and spectinomycin, while two farms discontinued use and one reduced use of cephalosporins.
- This multidisciplinary approach was effective in reducing antimicrobial drug use for calf diarrhoea on dairy farms without negative impacts on calf health.
Predicting sensitivity of repeated environmental sampling for Mycobacterium avium subsp. paratuberculosis in dairy herds using a Bayesian latent class model
Zoche-Golob et al., 2021
- 1x sample from manure concentration areas (end of scraper alleys, cow alleys) and 1x sample from manure storage areas (lagoons, piles or pits).
- To achieve a cumulative sensitivity of at least 0.9 with 95% probability, eight sampling events with two environmental samples per set, or four sampling events with four samples per set were required. Further model assessment demonstrated that these results can only be generalized to cattle populations with a similar within-herd prevalence to those studied here (approximately 0.08).
Survival of Streptococcus uberis on bedding substrates
Sherwin et al., 2021
- Streptococcus uberis survived on sand and wheat straw bedding for at least 35 days.
- Streptococcus uberis did not survive on clean or used sawdust for more than 7 days.
- Streptococcus uberis replicated on used sand and wheat straw bedding material.
- Differences in the ability of field strains to survive and replicate on different bedding substrates were noted and could be related to specific genomic differences and the marked genetic heterogeneity within this species
Status of claw recordings and claw health in Danish dairy cattle from 2013 to 2017
Capion et al., 2021
- The overall prevalence across breed and parity groups of:
o Digital dermatitis (DD) – 21%
o Interdigital hyperplasia (IH) – 6%
o Solar ulceration (SU) – 7%
o White line abscessation (WLA) – 3% - The prevalence of the lesions remained quite constant during the 5-year period.
- DD was recorded in 95% of the herds in 2017.
- The prevalence of IH, SU and WLA increased with increasing parity.
Bovine viral diarrhea virus (BVDV) infection: Effect on reproductive performance and milk yield in dairy herds
Arnaiz et al., 2021
- Fifteen herds did not use vaccines (G1) whereas the remaining 13 received modified live BVD virus (BVDV) vaccines (G2).
- In G1 herds, a significant increase in calving-conception interval (CCI) (13.8 days; 95% CI, 0.4–27.3 days; P = 0.050) was observed during the BVD outbreak compared to the year before the outbreak.
- In G2 herds, there was a not a significant increase in CCI (3.0 days; 95% CI, −1.2–7.2 days; P = 0.558).
- Changes in the mean number of inseminations per conception (AI/P) before/after outbreak periods were not significant in any of the herds.
- In G1 herds, there was an increase of 0.09 units (P > 0.05) during the outbreak, whereas in G2 herds, AI/P decreased 0.08 units (P > 0.05).
- Compared to milk production in the year before the BVD outbreak, there was no significant change in G1 herds throughout the study period (P > 0.05), but there were significant increases in G2 herds over the study period (P1–P2, 1.4 kg/day increase, P = 0.019; P1–P3, 2.0 kg/day increase, P = 0.007).
- BVDV infection affected reproductive performance, which is critical in maintaining dairy herd profitability.
- The administration of modified-live vaccine (MLV) mitigated the negative effects of BVDV on reproduction
Characteristics (sensitivity and specificity) of herd-level diagnostic tests for Mycobacterium avium subspecies paratuberculosis in cattle — A systematic review
Field et al., 2022
- Whole herd ELISA
o HSe varied between 83-100% when a single seropositive animal was used to define a herd as positive
o HSp did not increase above 91% in any scenario – individual animal serology is inefficient for correctly identifying infected herds, although Sp can be improved via serial testing. - Whole-herd ELISA testing with follow-up faecal culture or PCR of seropositive animals
o Used to overcome the imperfect HSp of WHT-ELISA
o In low prevalence herds, the poor sensitivity of individual faecal culture results in a vastly reduced sensitivity if this approach is taken (Sergant et al., 2019) - Random or targeted ELISA
o A random sample of 30 animals associated with a HSe of 61% (Wells et al., 2002)
o Targeted ELISA increased the probability of detection by x1.1-1.6 (Tavornpanich et al., 2006) - Bulk milk ELISA
o Herd sensitivity estimates for BMT ELISA vary between 8–30% when using manufacturers’ recommended S/P ratios.
o HSe was increased when BM ELISA was performed at WHP >5% - Individual faecal testing
o Tavornpanich et al. (2008) estimated the HSe of IFC to range from 44 to 100%, increasing as sample size and WHP increased - Pooled faecal testing
o HSe estimates ranged from 26 to 100%, and HSp estimates ranged from 98 to 100%
o In studies that compared multiple herd-level screening tests in the same sample population, pooled faecal testing had the highest reported HSe after individual faecal testing when considering tests with 100% HSp (Sergant et al., 2019). - Bulk milk tank culture, PCR or phage testing
- Environmental sampling
o The most common protocol used was collection of six composite samples from the main cow housing, manure storage and other areas such as the collecting yard and sick cow pens for testing by culture. HSe estimates for this six composite sample protocol ranged from 24% to 79%, and HSp in one study was 99%.
Direct comparisons between the reported HSe and HSp estimates of different studies is challenging due to the variations in herd prevalence and test protocols used. The data in this systematic review will benefit decision-makers and researchers and highlights knowledge gaps requiring further research.
Comparison of testing for failure of passive transfer in calf serum using four different testing methods
Denholm K. et al., 2022
- Failure of passive transfer (FPT) in calves is defined as failure to absorb colostral antibodies sufficient to achieve a serum immunoglobulin G (IgG) concentration of > 10 g/L within the first week of life.
- FPT prevalence was estimated to be 14.17% (95% confidence intervals, 10.58-17.75) based on RID test results. 4
- Brix and TP refractometry underestimated IgG concentration, resulting in an overestimation of FPT prevalence (40.54% and 29.46%, respectively). Similarly, ZST overestimated the prevalence of FPT (46.29%), but the variability was more consistent across all IgG concentrations.
- The performance of all three indirect methods was improved by lowering test cutpoints (to 5 g/dL for TP; 8.2% for Brix; 15 units for ZST) which improved test specificity and accuracy of these screening tests.
Cow-related factors associated with intramammary infections during the 1st week postpartum in primiparous dairy cows in certified organic herds
Fernandes et al., 2022
- Intramammary infection was observed in 58.7% of cows, with Staphylococcus chromogenes and S. aureus being the most prevalent pathogens.
- Cows with milk leakage at 1st week postpartum were at 3.42 greater odds of IMI (P < 0.01).
- Cows with prepartum BCS ≥ 3.75 were at 3.12 greater odds of IMI (P < 0.01).
- Cows with milk leakage in the 1st week of lactation had increased SCC (P < 0.01) and lower milk production in the second month of lactation (P = 0.05).
Early life indicators of first lactation milk yield and the effect of treatment for bovine respiratory disease on survivability and risk of pregnancy in Holstein dairy cattle
Hurst et al., 2022
- Season born, ADG (0–400 days), milk production potential, and heifer conception age had a significant impact on 305-day first lactation milk production (all P ≤ 0.05; r2 = 0.31).
- Calves treated for BRD from 61 to 120 days old had a significantly lower chance of survival to 850 days of age than animals not treated for BRD. Additionally, calves treated for BRD from 61 to 120 days old had reduced risk of pregnancy. The results show the impact of early life on future milk production, survivability, and pregnancy risk on a commercial dairy herd.
Dynamics of Mycoplasma bovis in Dutch dairy herds during acute clinical outbreaks
Penterman et al., 2022
- Twenty farms were followed with laboratory testing of suspected dairy cows. Each outbreak farm was sampled five times, at 2–3 week intervals.
- 60% (12/20) of the herds showed a combination of arthritis and mastitis, while other herds experienced only clinically mastitis (15%; 3/20) or arthritis (25%; 5/20).
- From the time an outbreak was confirmed, M. bovis infection was not only present in dairy cows, but also in young stock and calves (80% of the farms).
- Laboratory tests also confirmed the presence of M. bovis in healthy animals.
- The M. bovis PCR levels of calves and young stock were highly correlated at all visits (rtotal = 0.81, P < 0.01).
- Furthermore, M. bovis was present in the environment of the animals.
- At the end of the 3-month study period, none of the 20 clinical outbreak farms were M. bovis-‘negative’, based on laboratory testing, although hardly any clinical cases were observed at that time.
The effect of pre-calving injection of trace mineral supplements on periparturient disease incidence in pasture based dairy cows
Bates et al.
subcutaneous injection of 5.5 mL of TMS (40 mg zinc, 10 mg manganese, 5 mg selenium, 15 mg copper per mL), 14–28 days before planned start of calving
From −7 to PSC +30 days, TMS reduced the adjusted hazard ratio (HR) for CM at quarter and cow level (P < 0.001), with no evidence for an effect beyond 30 days.
- The adjusted OR (and 95% highest density interval, HDI) for the effect of TMS on CM from −7 to PSC +30 days was 0.40 (95% HDI, 0.26–0.63) at quarter level, 0.51 (95% HDI, 0.38–0.69) at cow level and for SCM, 0.72 (95% HDI, 0.54–0.95).
- The difference in CM incidence from TMS at the cow level was −2.0% (95% HDI, −3.4 to −1.1%) and −1.2% (95% HDI, −3.2 to − 0.6%) at quarter level.
- No clear effect was identified of TMS on cumulative incidence of PVD.
Comparison of claw horn disruption lesions in four dairy herds using two different trimming techniques: A case study
Capion et al., 2022
two different trimming methods - the traditional Danish Method (DAM) and the White Line Atlas Method (WLAM).
- There were significant differences between trimming methods for sole haemorrhage (odds ratio = 0.44), sole ulcer (odds ratio = 0.42), and white line separation (odds ratio = 0.64), with a lower prevalence during the period of trimming with the WLAM.
- No significant difference between trimming methods could be found in the occurrence of white line abscess or double sole.
- The lower prevalence of claw horn disruption lesions found in this study when cows were trimmed with WLAM justifies and necessitates further experimental studies of claw trimming methods to validate these findings.
Distinct Mannheimia haemolytica serotypes isolated from fatal infections in veal calves and dairy cows
Lam et al. 2023
- Among the 96 M. haemolytica isolates, 93 were shown to belong to either of two large clusters, with 48/51 calf isolates belonging to one, and 43/45 cow isolates and two calf isolates from cases of FPP to the other.
- All M. haemolytica isolates from veal calves with FPS were of serotype A2, whereas the isolates from dairy cows and two calves with FPP were predominantly of serotypes A1 and A6.
- Most serotype A2 isolates from veal calves with FPS (95.6 %) contained multiple antibiotic resistance genes (ARGs) against three to five antimicrobial classes (phenicols, sulphonamides, tetracyclines, aminoglycosides or beta-lactams).
- In contrast, these ARGs were only present in 10.8 % of M. haemolytica A1 and A6 isolates from pneumonic adult cattle and absent in isolates from the two calves with FPP.
- These two disease presentations appear to be caused by genetically distinct strains with different antimicrobial resistance gene patterns.
- While M. haemolytica serotype A2 is generally considered to be a commensal microorganism of cattle, it was clearly associated with fatal FPS in veal calves in the Netherlands.
