Wieland Matthias, Ten Have Heleen
Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY 14853, USA.
Lely Industries N.V., 3147 PB Maassluis, The Netherlands.
Animals (Basel). 2025 Mar 31;15(7):1011. doi: 10.3390/ani15071011.
This retrospective cohort study examined the association between delayed milk ejection (DME), defined as bimodal milk flow, and milk yield in dairy cows milked with an automated milking system (AMS). Additionally, we identified risk factors for DME. Using data from a farm milking approximately 1350 cows, we analyzed 689,484 individual milking records and 194,142 daily cow observations over 350 days with generalized linear mixed models. Cows with DME generally had higher daily milk yields, regardless of lactation number. However, first-lactation cows early in lactation and older cows (≥third lactation) late in lactation produced less milk when experiencing DME. In contrast to the higher daily milk yield, cows produced less milk per milking when experiencing delayed milk ejection. However, more frequent milkings contributed to higher daily milk yield, even with more instances of delayed milk ejection. Risk factors for DME included lactation number, stage of lactation, milking frequency, and milking interval. These findings underscore the complexity of DME in AMS and suggest that optimizing individualized milking protocols could improve milk yield efficiency. Understanding the interplay of cow characteristics and milking management may enhance AMS performance and dairy herd productivity.
这项回顾性队列研究调查了采用自动挤奶系统（AMS）挤奶的奶牛中，以双峰奶流定义的泌乳延迟（DME）与产奶量之间的关联。此外，我们还确定了DME的风险因素。利用一个约有1350头奶牛的农场的数据，我们使用广义线性混合模型分析了689484条个体挤奶记录和350天内194142条奶牛日观测数据。无论泌乳次数如何，出现DME的奶牛通常日产奶量更高。然而，泌乳早期的头胎奶牛和泌乳后期的老龄奶牛（≥第三胎）出现DME时产奶量较低。与较高的日产奶量形成对比的是，出现泌乳延迟时奶牛每次挤奶的产奶量较少。然而，即使有更多泌乳延迟的情况，更频繁的挤奶也有助于提高日产奶量。DME的风险因素包括泌乳次数、泌乳阶段、挤奶频率和挤奶间隔。这些发现强调了AMS中DME的复杂性，并表明优化个性化挤奶方案可以提高产奶效率。了解奶牛特征与挤奶管理之间的相互作用可能会提高AMS的性能和奶牛群的生产力。
