Selection effect for growth traits on energy requirements in beef Nelore steers

Author(s)

Solar Diaz, Iara Del Pilar ; Framartino Bezerra, Luis Antonio ; Lobo, Raysildo Barbosa ; de Araujo Neto, Francisco Ribeiro ; Ferreira de Camargo, Gregorio Miguel ; Rocha da Cruz, Valdecy Aparecida ; Costa, Raphael Bermal ; de Oliveira, Henrique Nunes

• Document type: Journal article
• Source: TROPICAL ANIMAL HEALTH AND PRODUCTION; v. 54, n. 4, p. 9-pg., 2022-08-01.

Abstract

Growth data of 77,372 Nelore steers were used to estimate the selection effect on energy requirements considering two beef production systems: cow-calf and slaughter cycles. All the animals had measures from 120 days to 7 years old. The parameters necessary to evaluate the selection effect on energy requirements were obtained by random regression analysis using Legendre polynomials. The models included additive direct and maternal effects, and animal and maternal permanent environmental effects as random terms. Contemporary group and dam age at calving (linear and quadratic effect) were included as fixed effects, and orthogonal Legendre polynomials of animal age (cubic regression) were considered random covariables. The coefficients from the model M3353_5 were used to calculate the genetic gains necessary to predict the increase in phenotypes. The selection was simulated for body weight (BW) and weight gain (WG) at different ages and energy requirements were calculated using NRC equations. The cost of feed was calculated for a cow-calf and slaughter cycle of production considering a system of Brachiaria decumbens pasture without supplementation. In slaughter system, the selection for weight of 365 days of age is the best option. In cow-calf systems, the selection W120 is the best choice. (AU)

• FAPESP's process: 09/04490-7 - Effect of selection for growth at different ages on energy consumption in the Nellore cattle
• Grantee: Iara Del Pilar Solar Diaz
• Support Opportunities: Scholarships in Brazil - Doctorate