R. Bras. Zootec.29/Apr/2025;54:e20230004.
Anti-Müllerian hormone concentration and scrotal circumference as predictors of fertility-linked characteristics in male Brahman and Simmental bulls
Renata Maculan
, Jesús Alfonso Sánchez Viafara
, Gisvani Lopes de Vasconcelos
, Gabriel Miranda Moreira
, Cintia Vanin Ribeiro
, Nathália Alves
, Marcos Brandão Dias Ferreira
, José Camisão de Souza
ABSTRACT
This study investigates whether pre-pubertal scrotal circumference (SC) and anti-Müllerian hormone (AMH) concentrations indicate sexual precocity in Brahman and Simmental bulls. Fifty-three bulls (Brahman, n = 27; Simmental, n = 26) were used. Scrotal circumference was measured at three periods: pre-puberty (Brahman = 19.99±0.20 months; Simmental = 9.13±0.17 months), puberty (Brahman = 21.42±0.20 months; Simmental = 18.26±0.17 months), and post-puberty (Brahman = 33.34±0.55 months; Simmental = 24.07±0.17 months). A single sample taken at the pre-pubertal period was used for the AMH determination. Two classes were defined based on the frequency distribution of AMH concentrations: low AMH <2.28 ng/mL and high AMH ≥2.28 ng/mL. Scrotal circumference was negatively correlated with the percentage of total defects (r = −0.5957; P = 0.0246) and positively correlated with the percentage of normal sperm (r = 0.595; P = 0.0265). There was a high correlation between SC and assessment periods (pre-puberty, puberty, and sexual maturity) in both breeds (Brahman: r = 0.8776; P = 0.0005; Simmental: r = 0.7483; P = 0.0002). At puberty, SC was higher (P = 0.0002) in animals of the low AMH class (34.78±0.78 cm) than in the high AMH class (32.47±0.42 cm). Males classified as having low AMH concentration had better (P<0.0001) andrological assessments, (vigorous oscillatory movement or vigor: 3.92±0.20; sperm mass movement or turbulence: 2.63±0.19; progressive motility: 77.55±3.80) than those classified as having high AMH concentration (vigor = 3.33±0.19; turbulence = 2.06±0.19; progressive motility = 65.14±3.79). Pre-pubertal AMH concentrations are negatively correlated with SC and are a good predictor of sexual precocity in Brahman and Simmental bulls.
Keywords: AMH; bull selection; sexual precocity; sperm