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

处于从干期到哺乳期过渡阶段的奶牛有患诸如酮症等产后疾病的风险，这可能进一步增加它们患其他健康和生殖疾病的风险。亚临床酮症（SCK）影响许多奶牛，在加拿大奶牛群中估计发病率为40%。SCK是哺乳期早期过度负能量平衡的结果。来自加拿大安大略省的最新研究数据表明，在机器人挤奶系统中挤奶的奶牛患SCK的风险更大。由于其他健康问题（瘤胃酸中毒）的风险增加，在哺乳期早期大量补充传统的机器人浓缩物（通常淀粉含量高）是有问题的。因此，在产后早期，提供一种具有高糖潜能的替代能源可能是更可取的。这种具有高糖潜能的饲料补充物的一个例子是甘油。甘油很容易以合理的成本获得，因为它是生物柴油工业的副产品，而世界范围内生物柴油的产量正在不断增加。因此，本研究的目的是确定产犊前和产犊后补充甘油是否可以改善机器人系统中奶牛的代谢健康、瘤胃稳定性和生产力。在两项研究中，我们将检验饲喂甘油对过渡奶牛的预期益处。我们预测，添加甘油将提高奶牛的干物质采食量、瘤胃健康和代谢状态，以及随后的产奶量和效率。根据这些结果，我们希望开发出最佳的管理方法来喂养过渡期奶牛，不仅可以改善奶牛的健康和福利，还可以提高生产效率。反过来，这将帮助乳制品生产商获得更多利润，同时也增强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.