Non-carcass components of three genetic beef cattle group finished in feedlot or rotational grazing with supplementation

Abstract

Foram avaliados os componentes nãointegrantes da carcaça de bovinos castrados (novilhos) Brahman, Brangus e Hereford terminados em confinamento ou pastejo com suplementação (capim-mombaça). Os animais foram abatidos com espessura de gordura subcutânea superior a 4mm. A dieta do confinamento foi formulada com 60% de volumoso e 40% de concentrado, com 13% PB e 62% NDT. O capim mombaça apresentou 7% de PB e 56%NDT e o suplemento apresentou 24% PB e 76% NDT. O delineamento experimental foi inteiramente casualizado, com arranjo fatorial 3x2 (três grupos genéticos e dois sistemas de terminação) e as médias foram comparadas pelo teste de Tukey ajustado. Foram observadas diferenças significativas para o peso de abate (PA) e peso do corpo vazio (PCV) favorável aos animais mantidos em pastejo com suplementação (444,03 vs 416,50kg para PA e 409,68 vs 375,24kg para PCV), entretanto não houve diferença significativa entre os sistemas de terminação para o rendimento de corpo vazio (RCV). O menor percentual de órgãos vitais foi apresentado pela raça Brahman independente do sistema de terminação utilizado (2,19%). A mesma tendência foi observada para o trato digestivo com um percentual de participação de 3,77% PCV do Brahman vs 4,87% e 4,48% PCV do Hereford e Brangus, respectivamente. Os novilhos Brahman apresentaram menores pesos de coração, pulmão e baço que os Hereford e Brangus. Os animais terminados em pastejo apresentaram maiores pesos de abomaso, pulmão e rins que os terminados em confinamento, 0,47 vs 0,35% PCV; 0,77 vs 0,71% PCV e 0,77 vs 0,71% PCV, respectivamente.The non-carcass components of steers from Brahman, Brangus and Hereford finished in feedlot or pasture with supplementation (mombaça grass) were evaluated. The animals were finished when subcutaneous fat thickness was over 4mm. The feedlot diets have roughage:concentrate ratio of 60: 40, with 13% CP crude protein and 62% TDN. The level of CP of mombaça grass was 7% with 56% TDN, and the supplement was 24% CP and 76% TDN. The experimental design was completely randomized with a 3x2 factorial arrangement (three genetic groups and two finishing systems) and means was compared by adjust Tukey test. Significant difference was observed for the slaughter weight (SW) and empty body weight (EBW) in steers maintained at pasture with supplementation. (409.68 versus 375.24kg of empty body weight), however, no differences were observed with the percentage of empty body dressing percentage (EBD). Brahman steers has the lowest percentage of vital organs independent of finishing system (2.19%). Same trend was showed for the total empty digestive tract with 3.77% for Brahman steers vs 4.87 and 4.48% EBW of Hereford and Brangus. The Brahman steers had lower weights of heart, lung and spleen than the Hereford and Brangus. Animals finished on pasture had greater weight of abomasums lung and kidneys than animals finished on feedlot 0.47 vs 0.35% EBW; 0.77 vs 0.71% EBW and 0.77 vs 0.71% EBW, respectively