Wieland Matthias, Virkler Paul Douglas, Sipka Anja
Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY 14853, USA.
Animals (Basel). 2021 Oct 3;11(10):2883. doi: 10.3390/ani11102883.
The aims of the research were to: (1) describe a protocol for the identification of cows that are subjected repeatedly to a forced retraction event at the end of milking; (2) study risk factors of repeated forced take-off (RFTO); and (3) assess the average milk flow rate at which the forced retraction event occurred. In a retrospective study, we collected milk flow data over a 1-week period from a 4300-cow dairy with a rotary milking parlor and a thrice-daily milking schedule. We identified 109 cases of RFTO and 2467 controls. A multivariable logistic regression model revealed associations of parity, stage of lactation, average daily milk production, and milking speed with RFTO. Cows in parity 3 or greater, animals ≤100 days in milk, high-producing animals, and cows with low milking speed had higher odds of RFTO. The average (least squares means (95% CI)) milk flow rates at the time of removal of the milking unit were 2.1 (2.0-2.1) kg/min in milking observations that were terminated with the forced retract and 1.5 (1.4-1.5) kg/min when milking units were removed with the automatic cluster remover. Future research to better understand the effect of RFTO on milk production, udder health, and animal well-being is warranted.
（1）描述一种用于识别在挤奶结束时反复经历强制回退事件的奶牛的方案；（2）研究反复强制回退（RFTO）的风险因素；（3）评估强制回退事件发生时的平均奶流速度。在一项回顾性研究中，我们从一个拥有4300头奶牛的奶牛场收集了为期1周的奶流数据，该奶牛场采用旋转式挤奶厅，每天挤奶三次。我们确定了109例RFTO病例和2467例对照。多变量逻辑回归模型揭示了胎次、泌乳阶段、日均产奶量和挤奶速度与RFTO之间的关联。第3胎及以上胎次的奶牛、产奶≤100天的奶牛、高产奶牛以及挤奶速度慢的奶牛发生RFTO的几率更高。在因强制回退而终止的挤奶观察中，移除挤奶设备时的平均（最小二乘均值（95%置信区间））奶流速度为2.1（2.0 - 2.1）千克/分钟，而在使用自动脱杯器移除挤奶设备时，奶流速度为1.5（1.4 - 1.5）千克/分钟。有必要开展进一步的研究，以更好地了解RFTO对产奶量、乳房健康和动物福利的影响。
