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Abstract：
Ambient temperatures that result in body temperatures beyond those of the thermo-neutral zone for dairy cattle can lead to reduced reproductive efficiencies that have negative effects on economic and productive efficiencies of dairy farms. In addition, in pregnant cows, ambient temperature-induced heat stress leads to modifications in the epigenome of the developing embryo, which, in turn, could lead to phenotypic variations in the sexually mature animal and its offspring. In the mammalian response to stress, adrenocorticotropic hormone stimulates the synthesis and secretion of glucocorticoids, which may have detrimental effects on the hypothalamic-pituitary-gonadal axis and the female estrous cycle. The aim of this review is to describe the effects of ambient heat stress on the reproductive system of dairy cattle and its potential trans-generational effects. There are many heat stress occurrences in dairy cattle during a large portion of the year in many countries and there is an increase in incidence with the onset of global warming. These heat stress conditions make it possible that the embryo/fetus of cows may be affected when heat stress conditions prevail in ways that there is impaired fertility of the sexually mature cows that develop from these embryos/fetuses. This is the outcome because of molecular changes in ovarian glucocorticoid response caused by epigenetic modifications established during fetal development.
摘要：
环境温度导致体温超出奶牛的热中性区域，可能导致繁殖效率降低，对奶牛场的经济和生产效率产生负面影响。此外,在怀孕的奶牛中，环境温度诱导的热应激导致发育中胚胎的表观基因组发生变化，which,反过来,可能导致性成熟动物及其后代的表型变异。在哺乳动物对压力的反应中，促肾上腺皮质激素刺激糖皮质激素的合成和分泌，这可能对下丘脑-垂体-性腺轴和女性发情周期产生不利影响。这篇综述的目的是描述环境热应激对奶牛生殖系统的影响及其潜在的跨代效应。在许多国家，一年中的大部分时间里，奶牛都会发生许多热应激，并且随着全球变暖的开始，发病率也在增加。这些热应激条件使得当热应激条件以从这些胚胎/胎儿发育的性成熟奶牛的生育力受损的方式盛行时,奶牛的胚胎/胎儿可能受到影响。这是由于在胎儿发育过程中建立的表观遗传修饰引起的卵巢糖皮质激素反应的分子变化而导致的结果。
