Evaluation of corn processing and lasalocid Nellore cattle finishing in high dry supplementation system

Abstract

The present study aims the evaluation of effect of corn processing and inclusion of lasalocid sodium on the termination of Nellore bovines in grazing of Brachiaria brizantha cv. Marandu, in system of high supplementation in dry season, on performance, carcass characteristics and ruminal parameters. The experiment will be carried out at the research unit of Polo Regional de Desenvolvimento Tecnológico dos Agronegócios da Alta Mogiana (PRDTA - Alta Mogiana), Colina - SP, Agência Paulista de Tecnologia dos Agronegócios. The experimental period will be conducted from July to November, which will be divided into four periods of 28 days each, in a total of 112 days of experiments. Will be used 68 bovines, uncastrated, Nellore, with an average body weight of approximately 370 kg. From that amount, four will be slaughtered at the beginning of the experiment, in order to estimate the carcass traits and metabolic organs. Moreover, will be utilized 12 Nellore bovines castrated and fistulated in the rumen for evaluation of intake and ruminal parameters. The treatments will consist of a factorial 2 x 2, being the first factor the type of corn processing (Dry corn or corn silage with high moisture content) and the second factor will be use of additive (with or without inclusion of lasalocid sodium). The animals will receive supplement ad libitum, with 60% inclusion of corn in the concentrate and the dose of lasalocid used will be 36 mg / kg of concentrate dry matter. The method of grazing used will be continuous stocking, with variable stocking rate. The quantitative and qualitative analysis forage and animal weighing will be performed every 28 days. Evaluation of grazing and supplement intake and ruminal parameters (pH, nitrogen amonniacal and short chain fatty acids) will be held every 21 days. At the end of the experiment, all animals will be slaughtered and their carcass evaluated for hot and cold carcass weight, yield of hot and cold carcass, losses by cooling. They will be drawn two animals per paddock to measure weight and yield of primary cuts, the weight of the main metabolic organs, pH, biometric measurements, loin eye area and subcutaneous fat thickness in the Longissimus muscle and the chemical composition by section HH. The experimental unit adopted will be the paddock, totaling 16 paddocks, consisting of four animals each, and four replicates per treatment. The variables will be analyzed in a randomized block design, factorial (2 x 2) with repeated measures over time using the procedure MIXED do SAS version 9.2 (SAS, 2008). The averages are compared by t test at 10% probability. The consumption variables and ruminal parameters will be analyzed in Latin square, with three squares with four animals each. The data obtained over time (pH, nitrogen amonniacal and short chain fatty acids) will be analyzed as repeated measures and the effects of time and the interaction between time (0, 6, 12 e 18 h) and treatment. (AU)