PSVII-29 Genetic analysis of frame score and performance traits in Nellore cattle – reproduction and productivity traits

Abstract

Frame score systems developed for Bos taurus breeds do not translate well for Bos indicus breeds, as these tend to be taller. We evaluated a novel frame score system for Nellore cattle raised on pasture [Guimaraes et al., 2020 J, Anim. Sci. 98 (Suppl. 4)]. Traits included adjusted scrotal circumference (cm) at 365 (SC365) and 450 (SC450) days of age, age at first calving (AFC, d), early heifer pregnancy (EHP, % calving as two-year-olds), stayability (STAY, % of cows remaining in the herd over 76 months of age, calving at least three times), and accumulated productivity (AP, kg of calf weaned per cow per year). In this study, we applied the previously developed equations (that also include hip height (HH, cm) and age to 12,049 records from the National Association of Breeders and Researchers (ANCP) database:FSmales= -20.35 + 0.1305*REA + 0.2633*BF - 0.5901*RF + 0.1139*HH + 0.0056*AGEFSfemales = -11.87 + 0.1316*REA - 0.2457*BF - 0.6218*RF + 0.1139*HH + 0.0009507*AGEThe (co)variance components and genetic parameters were estimated using a linear animal model or a threshold animal model depending on the trait. The heritability estimate for frame score was moderate (0.30). Estimated genetic correlations for reproductive traits were low to moderate (SC365, 0.06; SC450, 0.04; AFC, 0.18; EHP, -0.24; STAY, 0.06; AP, 0.25). The estimates support the notion that larger frame animals are later maturing but have greater lifetime productivity. The new frame score may be a useful tool for genetic selection of animals that are best suited to their environment.

Características de las ondas de desarrollo folicular en vaquillas prepúberes Bos taurus indicus de dos tallas diferentes

“…En relación con lo anterior, la información disponible indica que se requiere un mínimo de grasa corporal, la cual está altamente correlacionada con los parámetros de composición corporal, para detonar procesos reproductivos como la PB en vaquillas (Zieba et al, 2005;Perry, 2012;Hernández et al, 2021). Recientemente, Baldi et al (2021) realizaron un análisis genético con animales de la raza Nelore y observaron que aquellos con un frame score alto tardaron más en alcanzar la madurez reproductiva, pero tuvieron una vida productiva más larga.…”