Institute of Animal Science, University of Bonn, 53115 Bonn, Germany.
Domest Anim Endocrinol. 2022 Jul;80:106723. doi: 10.1016/j.domaniend.2022.106723. Epub 2022 Feb 27.
With global warming, the incidence of heat stress in dairy cows is increasing in many countries. Temperatures outside the thermoneutral zone (heat stress) are one of the environmental factors with the greatest impact on milk production and reproductive performance of dairy cows. In addition to several biological mechanisms that may contribute to the effects of fetal programming, epigenetic modifications have also been investigated as possible mediators of the observed associations between maternal heat stress during late gestation and performance and health later in life. In utero programming of these offspring may coordinate changes in thermoregulation, mammary gland development, and milk production ability at different developmental stages. This review examines the effects of prenatal and postnatal hyperthermia on the developmental outcomes of dairy cows, as well as the physiological and molecular mechanisms that may be responsible for the negative phenotypic consequences of heat stress that persist throughout the neonatal and adult periods and may have multigenerational implications. The physiological and molecular mechanisms underlying the negative phenotypic consequences of heat stress are discussed. Research challenges in this area, future research recommendations, and therapeutic applications are also discussed. In summary, strategies to reduce heat stress during the dry period should consider not only the productivity of the pregnant cow but also the well-being of the newborn calf.
随着全球变暖，许多国家奶牛的热应激发病率正在增加。热中性区以外的温度（热应激）是对奶牛产奶量和繁殖性能影响最大的环境因素之一。除了一些可能有助于胎儿编程影响的生物学机制外，还研究了表观遗传修饰作为观察到的母体妊娠晚期热应激与后代生命后期表现和健康之间关联的可能介导因素。这些后代的宫内编程可能协调了在不同发育阶段的体温调节、乳腺发育和产奶能力的变化。这篇综述检查了产前和产后过热对奶牛发育结果的影响，以及可能导致热应激持续存在于新生儿和成年期并可能具有多代影响的负表型后果的生理和分子机制。讨论了热应激负表型后果的生理和分子机制。还讨论了该领域的研究挑战、未来的研究建议和治疗应用。总之，在干奶期减少热应激的策略不仅应考虑怀孕奶牛的生产力，还应考虑新生牛犊的健康。
