Antral follicular count does not correlate with ovarian preantral follicular reserve in adult buffalo, Nelore, and crossbreed cattle

Aim of study: To investigate the correlation between antral and preantral ovarian follicular populations in adult cattle, given the discrepant previous reports, and to evaluate this correlation for the first time in buffalo. Area of study: Amazon region, North of Brazil. Material and methods: Ovaries of non-pregnant, adult, cycling, Bubalus bubalis (n=10), Bos indicus (Nelore; n=10), and Bos indicus × Bos taurus (Nelore × Angus crossbreed; n=10) were collected at the slaughterhouse, measured, and weighed. Antral follicles were counted (AFC), and the preantral population was estimated by histology. The correlation between ACF and preantral population was analyzed within each animal group, before and after categorizing females as low or high AFC. Main results: Nelore and crossbreed presented similar ovarian morphometry results (p>0.05), while buffalo (Bubalus bubalis) had the smallest and lightest ovaries (p0.05) amounts of preantral follicles, while crossbreed ovaries had the largest population (p