This study adds to the evidence that analgesia during disbudding is beneficial for calf productivity as well as calf welfare.
The performance of a new point-of-care diagnostic (Mastatest), an on-farm test designed to identify bacteria and provide antibiotic sensitivity testing information from milk samples, was compared with standard microbiological culture methods. A total of 292 milk samples from clinical mastitis cases in dairy cows on New Zealand dairy farms were examined, and latent class analysis was used to estimate the performance characteristics of both tests. Two hundred and fifty-six samples (87.7%) demonstrated bacterial infection in standard culture, and 269 (92.1%) using the point-of-care diagnostic. The most common bacterial species detected was Streptococcus uberis, found in 195 samples (66.8%) using standard culture and 190 samples (65.1%) using the point-of-care diagnostic. Latent class analysis found no significant differences in test characteristics between the point-of-care diagnostic and standard culture. The estimated sensitivity and specificity of the point-of-care diagnostic against all targets combined were 94.6 and 72.1% respectively; the corresponding estimates for standard culture were 90.5 and 73.9%. Comparison of antibiotic susceptibility testing using the point-of-care diagnostic and the reference method showed similar trends and, in some cases, identical MIC50 and MIC90 values, with at most one antibiotic dilution difference.
BackgroundJohne’s disease is a major production limiting disease of dairy cows. The disease is chronic, progressive, contagious and widespread; there is no treatment and there is no cure. Economic losses arise from decreased productivity through reduced growth, milk yield and fertility and capital losses due to premature culling or death. This study attempts to address the effect of subclinical JD on milk production under New Zealand pastoral dairy farming conditions using a new testing approach. Blood samples were taken from all lactating animals from a single seasonally calving New Zealand dairy herd in the autumn of 2013 and 2014. Samples were subject to serological assay for antibodies to Mycobacterium avium subsp. paratuberculosis using a combination of four ELISA tests in parallel followed by selective quantitative fecal PCR to confirm the fecal shedding characteristics of ELISA positive cows. ELISA status was classified as Not-Detected, Low, Moderate or High and fecal PCR status as Not-Detected, Moderate or High.ResultsA mixed generalized regression model indicated that, compared to cows where MAP was not detected, daily milk solids production was 4% less for high ELISA positive cows (p = 0.004), 6% less for moderate fPCR cows (p = 0.036) and 12% less for high fPCR cows (p < 0.001).ConclusionsThis study confirms that sub-clinical JD can have a significant impact on milk production and that the testing methodology used stratified the animals in this herd on their likely impact on production and disease spread. This allowed the farmer to prioritize removal of heavily shedding, less-productive animals and so reduce the risk of infection of young stock. This is the first longitudinal study based in New Zealand looking at the effect of Johne’s infection status on daily milk production allowing for intermediary and confounding factors.
This study adds to the evidence that pain management when disbudding is beneficial for calf productivity as well as calf welfare.
Endometritis, diagnosed either by assessing the proportion of nucleated cells that are neutrophils (PMN%) following cytology of the endometrium or by assessing the degree of purulent material within the vagina (purulent vaginal discharge or PVD score), is prevalent among dairy cows. However, limited data exist as to the degree of variation among herds in the prevalence of endometritis diagnosed by these 2 methods. Thus, we undertook a study involving uterine cytological and vaginal sampling at a median of 41 d in milk of 1,807 cows from 100 seasonally breeding dairy herds in New Zealand. The optimal cut-point for PMN% was determined by receiver operator characteristic (ROC) curve analysis using conception to first artificial insemination (AI) as the outcome variable. The prevalence of disease was then calculated at the cow and herd levels, and an estimate of the effect of clustering of cow within a herd was calculated. Reproductive outcomes were collated and associations between endometritis and reproductive outcomes assessed using multivariable models. The optimal PMN% cut-point was ≥2%. The correlation of results for cows within a herd (the intraclass correlation) was 0.03, which was significant; hence, subsequent modeling accounted for this clustering. The cow-level prevalence of PMN% ≥2% was 27.0% [95% confidence interval (CI): 25.0 to 29.1%], whereas the mean withinherd prevalence of PMN% ≥2% was 27.1% (95% CI: 24.7 to 29.6%; range: 5.0 to 63.6%), and the prevalence among herds varied significantly. An elevated PMN% (≥2%) was significantly associated with a reduction in the proportion of cows conceiving to first AI (45.8 vs. 54.5%), a reduced proportion of cows submitted for AI in the first 3 wk of the seasonal breeding program (83.7 vs. 89.3%), and a lower proportion pregnant in the first 3 (44.4 vs. 55.4%) and 6 wk (67.5 vs. 76.4%) of the breeding program relative to cows with a low PMN% (i.e., <2%). A total of 24.6% of cows had a PVD score ≥2. The herd mean prevalence of PVD score ≥2 was 25.1% (95% CI: 22.5 to 27.7%; range: 5.0 to 65.0%) and varied significantly among herds. The level of agreement (kappa) between the PVD score and PMN% was low (16.8%) and nonsignificant. The effects of PVD score and PMN% on reproductive outcomes were independent. The within-herd median prevalence of endometritis based on combining both diagnostic tests and using a Bayesian latent class model was 22.9% (Bayesian 95% CI: 10.4 to 40.1%). We conclude that more than onefifth of dairy cows have endometritis diagnosed either by PMN% or PVD in seasonal breeding herds when assessed at an average of 41 DIM, which was, on average, 30 d before the start of the seasonal breeding program. There is large and unexplained variation in prevalence of endometritis among herds. The 2 diagnostic methods were both associated with reproductive outcomes but have low levels of agreement between them and their effects appear to be independent.
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