Supplementing glycerol to transition dairy cows to improve metabolic status and productivity

从干奶期过渡到泌乳期的奶牛有患酮病等产后疾病的风险，这可能进一步增加其患其他健康和生殖疾病的风险。亚临床酮病（SCK）影响许多奶牛，在加拿大奶牛群中估计发病率>40%。SCK是泌乳早期过度负能量平衡的结果。加拿大安大略最近的研究数据表明，在机器人挤奶系统中挤奶的奶牛患SCK的风险更大。在泌乳早期，由于其他健康挑战（瘤胃酸中毒）的风险增加，传统机器人浓缩物（通常淀粉含量高）的更多补充是有问题的。因此，在产后早期提供具有高生糖潜力的替代能源可能是更理想的。这种具有高生糖潜力的饲料补充剂的实例是甘油。由于甘油是生物柴油工业的副产品，因此可以以合理的成本容易地获得甘油，生物柴油工业在世界范围内的生产量越来越大。因此，本研究的目的是确定产犊前后补充甘油是否可以改善机器人系统中挤奶的奶牛的代谢健康，瘤胃稳定性和生产力。在两项研究中，我们将研究向过渡期奶牛饲喂甘油的预期益处。我们预测，甘油补充剂将提高干物质摄入量，瘤胃健康，奶牛的代谢状态，以及随后的牛奶产量和效率。有了这些结果，我们希望开发出最佳的管理实践，用于喂养过渡期奶牛，不仅改善健康和福利，而且提高生产效率。这反过来将有助于乳制品生产商获得更多利润，同时也增加了消费者对这一农业部门的信心。

Dairy cows undergoing the transition from the dry period to lactation are at risk for developing post-partum diseases such as ketosis, which can further increase their risk of developing other health and reproductive disorders. Subclinical ketosis (SCK) impacts many dairy cows, with an estimated incidence of >40% in Canadian dairy herds. SCK is resultant of excessive negative energy balance in early lactation. Recent research data from Ontario, Canada showed that cows milked in robotic milking systems are at even greater risk of experiencing SCK. Greater supplementation of traditional robot concentrates, which are typically high in starch, in early lactation is problematic due to the increased risk of other health challenges (ruminal acidosis). Thus, providing an alternative energy source, with high glucogenic potential, may be more desirable during the early post-partum period. An example of such a feed supplement with high glucogenic potential is glycerol. Glycerol is readily available, at a reasonable cost, due to being a by-product of the biodiesel industry, which is being produced in growing amounts worldwide. Thus, the objective of this research is to determine if pre- and post-calving glycerol supplementation can improve metabolic health, rumen stability, and productivity of dairy cows milked in robotic systems. In two studies, we will examine the expected benefits of feeding glycerol to transition dairy cows. We predict that glycerol supplementation will enhance dry matter intake, rumen health, and the metabolic status of dairy cows, as well as their subsequent milk production and efficiency. With these results, we expected to develop best management practices for feeding transition dairy cows that not only result in improved health and welfare, but also production efficiency. This, in turn, will help dairy producers be more profitable, while also increasing consumer confidence in this agricultural sector.