FOLICULAR DYNAMICS, ENDOCRINE PROFILES AND ENDOMETRIAL GENE EXPRESSION IN FERTILE AND SUBFERTILE COWS

Carolina Viñoles; Andrea Alvez; Ximena Gonzalez; Ana Meikle Meikle

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

FOLICULAR DYNAMICS, ENDOCRINE PROFILES AND ENDOMETRIAL GENE EXPRESSION IN FERTILE AND SUBFERTILE COWS

Carolina Viñoles , Andrea Alvez, Ximena Gonzalez, Ana Meikle Meikle

Abstract

Context Subfertility has a negative impact on the productivity of beef cow herds; thus, it is relevant to unravel the mechanisms. Aims To study follicular development, body composition, concentrations of progesterone and metabolic hormones and their gene expression in the endometrium during the oestrus cycle. Methods Fertile and subfertile Hereford cows, were classified at 25 (n=84) and 60 (n=25) months-old, as: 1) fertile, pregnant at first insemination at 25 months, that became pregnant ≥ three out of five times at 60 months (n = 5); 2) subfertile, failed to became pregnant during three inseminations at 25 months, that became pregnant ≤ two of the five opportunities at 60 months (n = 6). Key results Fertile cows had greater concentrations of IGF-I, leptin and adiponectin (P<0.05); associated to differences in body composition. Insulin and progesterone concentrations were lower during the mid_ late luteal phase (P<0.05) in fertile than subfertile cows, with no impact on follicle dynamics. At dissection, healthy follicles from fertile cows tended (P<0.1) to have more granulosa cells and concentrations of IGF-I in the follicular fluid. Fertile cows had lower endometrial IGF-I mRNA expression (P<0.05), but tended (P<0.1) to have more progesterone and adiponectin 2 receptors expression on Day 7 of the oestrus cycle. Conclusions Differences in progesterone and metabolic hormones in plasma and follicular fluid and their endometrial expression are associated to the success of pregnancy in beef cows. Implications Strategies to improve the follicle and endometrial microenvironments are needed to improve the productivity of beef herds.

RD24160 Accepted 10 January 2025