Effect of the finishing system, rate of gain and slaughter criteria on meat quality characteristics of Angus x Nellore cattle

Abstract

The aim of this work is to evaluate the effect of the finishing system, weight gain rate and slaughter criterion on meat quality traits of castrated AngusxNellore males. The experiment will be carried out using a randomized block design (initial live weight) in a 2 x 2 x 2 factorial arrangement, with two finishing systems (pasture and confinement), two gain rates (high and low) and two slaughter criteria (slaughter weight and feed time). 75 Angus x Nellore castrated males, with initial mean weight of 390 ± 30 kg and 20 months of age, will be used. At the beginning of the experiment, three animals will be randomly separated to be slaughtered, as reference animals, as a way of comparing carcass characteristics, post mortem metabolism, muscle fiber characteristics and meat quality of the animals after the fattening period. Out of the remaining 72 animals, 36 animals will be housed in experimental confinement and 36 animals will be allocated in grass pickets containing Brachiaria brizantha cv. Marandu. In each finishing system (confinement and pasture) two distinct weight gain rates will be defined, in other words confinement with high rate of weight gain (18 animals), confinement with low rate of weight gain (18 animals), pasture with high rate of weight gain (18 animals) and pasture with low rate of daily weight gain (18 animals). In addition, out of the 18 animals from each production system mentioned above, nine animals will be slaughtered at 510 kg live weight and nine animals will be slaughtered after 120 days of feeding. During the experimental period, animal performance, blood profile and carcass characteristics by ultrasonography will be evaluated. After slaughter, metabolic profile, abundance of some glycolytic and oxidative enzymes, and the morphometric profile of two muscles (Longissimus and Semitendinosus) during postmortem will be evaluated. Meat quality characteristics such as color, cooking loss and shear force at different maturation times will be evaluated. In addition, sarcomere length, total intramuscular lipid concentration, shelf life, lipid oxidation, and fatty acid profile will be evaluated. Moreover, consumer acceptance analyzes will be performed by the consumer through sensorial analysis.