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Effect of nutritional plans in stocker grazing on growth physiology, metabolic parameters and meat quality of young bulls from different genetic types finished in pasture or feedlot

Grant number: 15/01147-0
Support type:Regular Research Grants
Duration: May 01, 2016 - October 31, 2018
Field of knowledge:Agronomical Sciences - Animal Husbandry
Principal Investigator:Telma Teresinha Berchielli
Grantee:Telma Teresinha Berchielli
Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
Assoc. researchers:Flávio Dutra de Resende ; Josiane Fonseca Lage ; Ricardo Andrade Reis

Abstract

This trial aims to evaluate the interactions between processesthat contribute with the animal's growth and this impact of meat quality of beef cattle from different genetic types submitted to two nutritional plans in stocker grazing during the rainy season and finished in pasture or feedlot in the dry season. Young bulls (n=162) will be used, with about 250 kg of BW from three genetic groups: Nellore, ½ Angus x ½ Nellore, Senepol. Initially, 18 animals will be slaughtered (six from each genetic group), that will be used as a reference group. After the adaptation period, the remaining animals (n=144) will be weighted after a 16-h solid fast to obtain the shrunk BW values. Forty eight animals from each genetic group will be allotted in a 2 x 3 factorial arrangement (two nutritional plans x three genetic groups), with 24 replicates for treatment. The nutritional plans will be: mineral salt and additive (virginiamycin) in 0.03% of BW or supplementation in 0.3% of BW with concentrate. The animals used in the first phase (stocker grazing) will be distributed in two finishing system, being realized in the pasture or feedlot in the dry season, with 24 animals (four of each treatment) slaughtered at the end of stocker grazing phase. At the finishing in the pasture or feedlot will be used 60 young bulls (on each system), from three genetic groups submitted the two nutritional plans in stocker grazing. Twenty animals from each genetic group will be used, being ten animals of each nutritional plan evaluated in the stocker grazing phase. All animals will be submitted in each system (pasture or feedlot) in a single diet, being daily fed with 2.0% of BW of concentrate. After 98 days of feeding, all animals will be slaughtered in the packing plant. The evaluations that will be realized: dry matter intake and feed efficiency, deposition of muscle and adipose tissue, blood parameters, average daily gain and carcass, adipogenesis and gene expression that involves the deposition of muscle and adipose tissue, and carcass and meat quality. At the same time, there will be a study of rumen metabolic parameters, which will be evaluated changes in ruminal microbiota, the efficiency of microbial synthesis and feeding behavior.Twelve animals will be used (four replicates per genetic groups) in a completely randomized design, repeated over the time (four periods), to evaluate these parameters of animals in the two finishing systems(confined and grazing). (AU)