Heat stress-induced dysregulation of bovine reproduction: A focus on corpus luteum and progesterone perspectives

Global warming and climate change pose significant challenges to cattle reproduction, with heat stress (HS) emerging as a critical factor contributing to infertility and subfertility in dairy cows. Elevated temperatures in high-producing cattle lead to declines in conception rates and increased incidences of early embryonic loss, thereby undermining the economic sustainability of dairy enterprises. HS induces a cascade of physiological, behavioral, and endocrinological responses, which adversely affect reproductive function, particularly through disruptions in corpus luteum (CL) activity and progesterone (P4) production—both essential for estrous cycle regulation and pregnancy maintenance. Prolonged HS exposure results in suppressed P4 secretion, which compromises the uterine environment necessary for embryo survival. This review examines the mechanisms by which HS impacts CL function and P4 synthesis, contributing to reproductive inefficiencies, and discusses evidence-based mitigation strategies, including environmental modifications, nutritional adjustments, hormonal interventions and genetic selection for thermotolerance. Through these insights, this review aims to highlight effective approaches to enhance fertility, reduce subfertility, and improve reproductive resilience in cattle facing HS-induced stress.