Veterinary Physiology, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland.
Veterinary Physiology, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland.
J Dairy Sci. 2019 Apr;102(4):2828-2843. doi: 10.3168/jds.2018-15713. Epub 2019 Feb 22.
Milk production of dairy cows has increased markedly during recent decades and continues to increase further. The evolutionarily conserved direction of nutrients to the mammary gland immediately after calving provided the basis for successful selective breeding toward higher performance. Considerable variation in adaptive responses toward energy and nutrient shortages exists; however, this variation in adaptability recently gained interest for identifying more metabolically robust dairy cows. Metabolic challenges during periods of high milk production considerably affect the immune system, reproductive performance, and product quality as well as animal welfare. Moreover, growing consumer concerns need to be taken into consideration because the public perception of industrialized dairy cow farming, the high dependency on feed sources suitable for human nutrition, and the apparently abundant use of antibiotics may affect the sales of dairy products. Breeding for high yield continues, but the metabolic challenges increasingly come close to the adaptational limits of meeting the mammary gland's requirements. The aim of the present review is to elucidate metabolic challenges and adaptational limitations at different functional stages of the mammary gland in dairy cows. From the challenges and adaptational limitations, we derive perspectives for sustainable milk production. Based on previous research, we highlight the importance of metabolic plasticity in adaptation mechanisms at different functional stages of the mammary gland. Metabolic adaptation and plasticity change among developing, nonlactating, remodeling, and lactational stages of the mammary gland. A higher metabolic plasticity in early-lactating dairy cows could be indicative of resilience, and a high performance level without an extraordinary occurrence of health disorders can be achieved.
奶牛的产奶量在最近几十年显著增加，并继续进一步增加。产后立即将营养物质向乳腺进化保守地输送，为成功选择具有更高性能的奶牛提供了基础。然而，在适应能量和营养短缺方面存在相当大的差异；但是，这种适应性的差异最近引起了人们的兴趣，因为它可以识别出代谢更稳健的奶牛。在高牛奶产量期间，代谢挑战会严重影响免疫系统、繁殖性能和产品质量以及动物福利。此外，由于公众对工业化奶牛养殖的看法、对适合人类营养的饲料来源的高度依赖以及抗生素的明显大量使用可能会影响乳制品的销售，因此需要考虑消费者日益增长的担忧。高产奶牛的培育仍在继续，但代谢挑战越来越接近满足乳腺需求的适应极限。本综述的目的是阐明奶牛乳腺不同功能阶段的代谢挑战和适应限制。从这些挑战和适应限制中，我们得出可持续牛奶生产的观点。基于以前的研究，我们强调了代谢可塑性在乳腺不同功能阶段适应机制中的重要性。代谢适应和可塑性在乳腺的发育、非泌乳、重塑和泌乳阶段之间发生变化。在泌乳早期，奶牛的代谢可塑性较高可能表明其具有恢复能力，并且可以在不出现异常健康问题的情况下实现高水平的性能。
