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

Ambient temperatures that result in body temperatures beyond those of the thermo-neutral zonefor dairy cattle can lead to reduced reproductive efficiencies that have negative effects on economicand 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 thesynthesis 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 describethe effects of ambient heat stress on the reproductive system of dairy cattle and its potentialtrans-generational effects. There are many heat stress occurrences in dairy cattle during a largeportion of the year in many countries and there is an increase in incidence with the onset ofglobal warming. These heat stress conditions make it possible that the embryo/fetus of cows maybe affected when heat stress conditions prevail in ways that there is impaired fertility of thesexually mature cows that develop from these embryos/fetuses. This is the outcome because ofmolecular changes in ovarian glucocorticoid response caused by epigenetic modifications establishedduring fetal development.