Fetal programming in dairy cows: Effect of heat stress on progeny fertility and associations with the hypothalamic-pituitary-adrenal axis functions

HUBER, E.; NOTARO, U.S.; RECCE, S.; RODRÍGUEZ, F.M.; ORTEGA, H.H.; SALVETTI, N.R.; REY, F.

ANIMAL REPRODUCTION SCIENCE

ELSEVIER SCIENCE BV

Año: 2020 vol. 216

0378-4320

Ambienttemperatures that result in body temperatures beyond those of thethermo-neutral zone for dairy cattle can lead to reduced reproductiveefficiencies that have negative effects on economic and productive efficienciesof dairy farms. In addition, in pregnant cows, ambient temperature-induced heatstress leads to modifications in the epigenome of the developing embryo, which,in turn, could lead to phenotypic variations in the sexually mature animal andits offspring. In the mammalian response to stress, adrenocorticotropic hormonestimulates the synthesis and secretion of glucocorticoids, which may havedetrimental effects on the hypothalamic-pituitary-gonadal axis and the femaleestrous cycle. The aim of this review is to describe the effects of ambientheat stress on the reproductive system of dairy cattle and its potential trans-generationaleffects. There are many heat stress occurrences in dairy cattle during a large portionof the year in many countries and there is an increase in incidence with theonset of global warming. These heat stress conditions make it possible that theembryo/fetus of cows may be affected when heat stress conditions prevail inways that there is impaired fertility of the sexually mature cows that developfrom these embryos/fetuses. This is the outcome because of molecular changes inovarian glucocorticoid response caused by epigenetic modifications established duringfetal development.