Feed efficiency and performance of beef cattle in finishing phase submitted to fetal programming

Abstract

The use of nutritional strategies aimed at increasing the productivity of beef cattle is essential to promote better zootechnical gains. Fetal programming (FP) encompasses adaptation mechanisms, in which the prenatal nutritional effects and uterine conditions, influence phenotypically in post birth progeny. However, the effects of FP in beef cattle in the termination phase are still partially unknown, especially in cattle production in tropical environments. The objective of this project is to evaluate the effects of FP on intake, feed efficiency, performance, and carcass traits of Nellore cattle at finishing phase. It will be used by 28 Nellore steers, with average age of 18 months with average initial weight of 420±45 kg, children of nulliparous heifers and a single Nellore bull. The fetal programming treatments were applied during the gestation of these males being divided into two nutritional plans: NP - mineral supplementation throughout pregnancy; and PC - mineral and protein-energy supplementation throughout pregnancy. After birth, all animals remained in the same environment and received the same sanitary and nutritional protocols. At 18 months the steers entered the finishing phase in confinement where the phenotypic data of the present project will be collected. The termination period will last 84 days, and dry matter intake (DMI) will be measured daily, every 14 days the animals will be weighed, the average daily gain (ADG) will be calculated and every 28 days the animals will be evaluated for carcass characteristics. Additionally, feed efficiency measures such as feed conversion rate (FCR) and residual feed intake (RFI) of the animals during the termination phase will be calculated. The data residuals will be tested for normality (Shapiro-Wilk test) and homoscedasticity (Levene test). The statistical analyses to determine the effects of treatments (NP and PC) on phenotypes will be performed by general linear models in the GLM procedure of the statistical package SAS 9.3 (SAS Institute Inc, 2011) considering significant the level of 5% probability. With this project, it is expected to be able to determine the phenotypic effects of fetal programming in the termination of Nellore cattle.