Short communication: Herd-level variables associated with overmilking in Michigan dairy herds

摘要

The objective of this study was to determine theherd-level variables that are associated with overmilkingin 64 Michigan dairy herds with a mean herd size of451 cows (range: 59–2,771 cows). Participating producerscompleted surveys to indicate their mastitis managementpractices and attitudes. Additionally, milkingprotocols were observed and milk flow dynamics for3,824 cows were estimated using digital vacuum recorders.The median duration of overmilking was 47 s (95%confidence interval, CI: 38.6 to 55.9 s), with a meanof 55% (95% CI: 49.5 to 61.1%) of cows within eachherd overmilked by at least 30 s. Median milking timefor all herds was 324 s (95% CI: 302 to 346 s) and wasfound to be positively correlated with median durationof overmilking (r = 0.670). Backward multivariateanalysis was used to determine which of 45 herd-levelmilking and management variables were associatedwith median duration of overmilking. Median durationof overmilking was negatively associated with the durationof time needed to complete 1 milking for the entireherd (adjusted R~2 = 0.13). Herds that operate milkingfacilities below maximum daily capacity may be proneto overmilking. Given the low coefficient of determination,variables unaccounted for in this study, such asequipment function or manual detachment by milkingoperators, are likely the most important risk factors forovermilking.