Feed eficiency, residual feed intake, heat production, carcass characteristics and meat quality in a herd of half-brothers of Nellore bovines

Abstract

Brazil, with the biggest commercial herd in the world, is just now developing research on the genetics of feed efficiency. In addition, it is impossible to ignore national and international pressure for a more sustainable beef production industry less polluting production, be the Amazon, Pantanal, Cerrado biome or anywhere. Countries like Australia and Canada have already developed programs to identify more efficient animals, that produce less pollutant, in search of molecular markers for feed efficiency and at the same time meat quality. Australia, with a 27 million bovine herd aims to reduce by approximately 30% the cost of meat production and by 10% methane emissions. Brazil with 205 million animals has an even greater challenge. The Laboratory of Animal Nutrition and Growth at ESALQ is a pioneer in this research line in the area and concluded four dissertations (Berndt, 2001; Calegare, 2004, Albertini and Farjalla 2007, 2010), three theses (Almeida, 2005, Calegare, 2008 and Albertini, 2010), studies in partnership with the Instituto de Zootecnia (Branco, 2006a, b), and two major ongoing projects FAPESP (No. 07/52028-5 and 09/01712-9) and CNPq (No. 471714/2009-7) which shows the necessary experience to conduct this test. This proposal is a continuation of the project No. 09/01712-9 whose goal will be to evaluate more than 125 Nellore, beyond the 300 already evaluated in a herd of half-siblings that have been formed four years ago, from the semen of 30 sires Summary of the National Nelore bulls. Individual consumption will be assessed, rates of feed efficiency, performance, individual production of heat obtained indirectly through the calibration of heart rate by O2 consumption, carcass characteristics (yield, size, ribeye area, fat thickness, weight of the kidneys, heart, liver, kidney fat, pelvic and groin), meat quality (color, pH, shear force, cooking loss, water retention capacity, rate of myofibrillar degradation and lipid IM), and respective correlations between these variables. The animals will be confined to the diet of 13% CP and 71% TDN until they reach 5 mm of fat thickness. This multi-institutional and multidisciplinary work, whose team of renowned geneticists, molecular biologists, experts in nutrition and quality of the meat should still allow the identification of molecular markers and to obtain estimates of breeding values of bulls for traits of tenderness, conversion, feed intake residual, and others. Furthermore, due to great difficulties in identifying efficient in converting food animals, a new objective for the project is the validation of theories Brosh et al. (2007) whose results suggest that the indirect measurement of heat production through the heart calibrated O2 consumption to be used for more efficient identification of animals. (AU)