Zhang Fan, Nan Xuemei, Wang Hui, Zhao Yiguang, Guo Yuming, Xiong Benhai
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Animals (Basel). 2020 Aug 28;10(9):1526. doi: 10.3390/ani10091526.
With the improvement in the intense genetic selection of dairy cows, advanced management strategies, and improved feed quality and disease control, milk production level has been greatly improved. However, the negative energy balance (NEB) is increasingly serious at the postpartum stage because the intake of nutrients cannot meet the demand of quickly improved milk production. The NEB leads to a large amount of body fat mobilization and consequently the elevated production of ketones, which causes metabolic diseases such as ketosis and fatty liver. The high milk production of dairy cows in early lactation aggravates NEB. The metabolic diseases lead to metabolic disorders, a decrease in reproductive performance, and lactation performance decline, seriously affecting the health and production of cows. Propylene glycol (PG) can alleviate NEB through gluconeogenesis and inhibit the synthesis of ketone bodies. In addition, PG improves milk yield, reproduction, and immune performance by improving plasma glucose and liver function in ketosis cows, and reduces milk fat percentage. However, a large dose of PG (above 500 g/d) has toxic and side effects in cows. The feeding method used was an oral drench. The combination of PG with some other additives can improve the effects in preventing ketosis. Overall, the present review summarizes the recent research progress in the impacts of NEB in dairy cows and the properties of PG in alleviating NEB and reducing the risk of ketosis.
随着奶牛高强度遗传选择、先进管理策略的改进以及饲料质量和疾病控制的提升，牛奶产量水平得到了极大提高。然而，产后阶段负能量平衡（NEB）日益严重，因为营养物质的摄入量无法满足快速提高的产奶需求。负能量平衡导致大量体脂动员，进而使酮体生成增加，引发酮病和脂肪肝等代谢疾病。奶牛泌乳早期的高产奶量加剧了负能量平衡。这些代谢疾病会导致代谢紊乱、繁殖性能下降以及泌乳性能降低，严重影响奶牛的健康和生产。丙二醇（PG）可通过糖异生作用缓解负能量平衡，并抑制酮体的合成。此外，丙二醇通过提高酮病奶牛的血糖水平和肝功能来提高产奶量、繁殖性能和免疫性能，并降低乳脂率。然而，大剂量的丙二醇（每天超过500克）对奶牛有有毒副作用。采用的饲喂方法是口服灌服。丙二醇与其他一些添加剂联合使用可提高预防酮病的效果。总体而言，本综述总结了近期关于奶牛负能量平衡影响以及丙二醇在缓解负能量平衡和降低酮病风险方面特性的研究进展。
