Fatores ambientes e estimativas de parâmetros genéticos do perímetro escrotal na raça Nelore

Abstract

The aims of this study were to estimate genetic parameters for scrotal circumference (SC) at 365 (SC365, n = 8,564), 455 (SC455, n = 7,463) and 550 (SC550, n = 4,447) days of age using different models and to verify the effect of adjustments for body weight and for weight gain (WG) on parameter estimates. Parameters were estimated using the REML methodology (MTDFREML), with an animal model and considering the relationship among 54,987 animals. The adjustment for weight and WG did not influence heritability (h2) estimates for SC at any age. No important difference among h2 estimates for SC in the three ages was observed. The h2 estimates ranged from.50 to.59 depending on the model. Results suggested that selection for SC would be effective. The best age for SC selection would be at 365 days.