Local cooling of the ovary and its implications for heat stress effects on reproduction

• Published in: Theriogenology Vol. 149; pp. 98 - 103
• Main Authors: López-Gatius, F., Hunter, R.H.F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.2020
• Subjects: Animals; Body Temperature - physiology; Cattle - physiology; Cold Temperature; Dairying - methods; Estrus - physiology; Female; Functional sperm reservoir; Heat-Shock Response - physiology; Ovarian Follicle - physiology; Ovarian physiology; Ovary - physiology; Ovulation - physiology; Ovulation failure; Reproduction - physiology; Seasons; Temperature gradients; Functional sperm reservoir; Ovulation failure; Temperature gradients; Ovarian physiology
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2020.03.029

The effects of season on the fertility of the dairy cow added to the metabolic stress of milk production are well known. We here present lactating dairy cows as a comparative model of this problem. This review examines the results of recent studies that have highlighted heat stress (HS) effects on pre-ovulatory follicles. From these studies, we draw information regarding the mechanisms giving rise to temperature gradients across reproductive tissues. Our review is completed by a discussion of approaches designed to reduce the negative effects of HS based on cooling strategies implemented before ovulation at or around estrus. •Direct measurements of intra-follicular temperature.•Pre-ovulatory follicles unequivocally cooler than rectum.•Follicular cooling is a prerequisite for ovulation.•Follicular cooling correlates positively with the potential for pregnancy.