Endometrial biopsy: a valuable clinical and research tool in bovine reproduction

Studies of postpartum endometrial physiologic and immune mechanisms in cows are compromised by the difficulty in acquiring tissue of suitable quality and in sufficient quantity (Bos taurus). Endometrial biopsy sampling has attracted concern regarding potential animal ill-health and perturbed subsequent fertility. Here, we describe a method of endometrial biopsy that obtains high-quality tissue samples and does not compromise fertility. Using a Hauptner instrument, endometrial biopsies were taken at 15, 30, and 60 d postpartum from 13 mixed-breed beef cows. The effects of repeat biopsy on health (heart rate, respiration rate, color of mucous membranes, rectal temperature), onset of estrous cyclicity, and first service conception rate were monitored. Extensive daily clinical examinations revealed no signs of ill-health. All cows had resumed estrous cyclicity at 60 d postpartum. A conception rate of 77% was achieved after estrus synchronization and artificial insemination. Each biopsy yielded intact endometrial tissue and nucleic acid suitable for extensive histologic and molecular analysis, respectively. We conclude that when carried out appropriately, bovine endometrial biopsy is a safe and reliable technique for assessing postpartum uterine function or health.