Study of genetic varibility of reproductive traits in Nellore bulls

Abstract

Heritabilities, were estimated of testicular traits, semen quality and libido in Nellore bulls. Records on 438 bulls registered from 1992 to 1997 were analyzed by single trait MTDFREML methodology using the animal model. The estimates obtained of heritability unadjusted and adjusted for body weight and the respective standard errors were: for scrotal circumference (0.81 ± 0.04 and 0.71 ± 0.07); testicular consistency (0.17 ± 0.09 and 0.17 ± 0.10); right testes length (0.42 ± 0.10 and 0.31 ± 0.11); left testes length (0.38 ± 0.10 and 0.30 ± 0.10); right testes width (0.78 ± 0.05 and 0.38 ± 0.12); left testes width (0.78 ± 0.05 and 0.34 ± 0.13); testicular volume (0.50 ± 0.09 and 0.30 ± 0.10); semen volume (0.20 ± 0.10 and 0.20 ± 0.10); sperm motility (0.15 ± 0.11 and 0.15±.11); sperm vigor (0.55 ± 0.10 and 0.54 ± 0.10); gross motility (0.07 ± 0.4 and 0.06 ± 0.4); major defects (0.59 ± 0.09 and 0.51 ± 0.11); minor defects (0.21 ±0.13 and 0.13 ± 0.11); total sperm defects (0.58 ± 0.09 and 0.48 ± 0.12) and libido (0.34 ± 0.10 and 0.19 ± 0.11).