Lucy Matthew C, Safranski Timothy J
Division of Animal Sciences, University of Missouri, Columbia, Missouri.
Mol Reprod Dev. 2017 Sep;84(9):946-956. doi: 10.1002/mrd.22844. Epub 2017 Jul 11.
Seasonal infertility is a significant problem in the swine industry, and may be influenced by photoperiod and heat stress. Heat stress during gestation in particular affects pregnancy, resulting in long-term developmental damage to the offspring. This review summarizes what is known about how heat stress on the pregnant sow affects lactation and her offspring. Sows responded to heat stress during gestation with increased rectal temperature, respiration rate, and skin temperature, and tended to reduce their activity-which may have changed their body composition, increasing the adipose-to-muscle ratio. Heat stress during gestation caused temporary insulin resistance during lactation, but this metabolic state did not seem to affect health, lactation, or rebreeding performance of the sow. Heat-stressed sows also presented with a shorter gestation period and reduced litter birth weight, although weaning weights are not affected when these sows are moved to thermoneutral conditions for lactation. The offspring of gestational heat-stressed sows, however, possessed unique phenotypes, including elevated body temperature, greater fat deposition, and impaired gonad development. Thus, gestational heat stress may significantly impact a herd through its effects on sows and their offspring. Further work is necessary to determine the magnitude of the effects across fa cilities and breeds.
季节性不育是养猪业中的一个重大问题，可能受光照周期和热应激的影响。特别是妊娠期的热应激会影响妊娠，对后代造成长期发育损害。这篇综述总结了关于妊娠母猪热应激如何影响泌乳及其后代的已知情况。妊娠期间的热应激使母猪的直肠温度、呼吸频率和皮肤温度升高，且活动量往往减少——这可能改变了它们的身体组成，增加了脂肪与肌肉的比例。妊娠期间的热应激导致泌乳期间出现暂时的胰岛素抵抗，但这种代谢状态似乎并未影响母猪的健康、泌乳或再次繁殖性能。热应激母猪的妊娠期也较短，产仔体重降低，不过当这些母猪转移到热中性条件下泌乳时，断奶体重不受影响。然而，妊娠期热应激母猪的后代具有独特的表型，包括体温升高、脂肪沉积增加和性腺发育受损。因此，妊娠期热应激可能通过对母猪及其后代的影响而显著影响猪群。有必要开展进一步研究以确定不同设施和品种间影响的程度。
