Efeito do plano nutricional prévio sobre o desempenho produtivo e as características de carcaça e da carne de machos nelore não castrados terminados em confinamento

• Autor(a) principal: Silva, Luiz Henrique Pereira
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5813
• topic: Bovino de corte - Alimentação; Bovino de corte - Carcaça; Nelore; Produtividade; Beef cattle - Feeding; Beef cattle - Housing; Nellore; Productivity; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

The present work was conducted aiming to evaluate the effects of feed restriction during post-weaning growing phase on animal performance, carcass traits and meat quality of Nellore feedlot finished with high-grain diet. To better discussing, the data were divided into two chapters; the first is about animal performance and carcass traits, while the second chapter is about meat quality. 39 young bulls with 8.5 ±0.2 months old and initial body weight of 230.4 ±5.6 kg, were used in this trial. At the beginning, five animals were slaughtered as reference group and the thirty-five remaining were allocated in one of the treatments, that were: low gain in growing phase and high gain in finishing (LH), medium gain in growing phase and high in finishing (MH) and high gain in both phases (HH). At the end of growing phase 5 LH, 6 MH and 6 HH animals were slaughtered and the remaining started the finishing phase and were slaughtered in the end of this phase. The intakes of dry mater (DM) and all nutrients did not differ (P>0.05) among the treatments when expressed as kg/d. However when DM and NDFap were expressed in g.kg BW-1.d- , were higher (P<0.05) for MH and LH than HH. The LH animals showed in the finishing phase greater (P<0.05) daily gain of body weight (BW) and empty body weight (EBW), greater carcass gain, greater carcass protein gain and greater carcass water gain than MH and HH. The LH and MH gain of non-carcass components was greater (P<0.05) than HH. The LH treatment had greater (P<0.05) feed efficiency and better carcass feed conversion than MH and HH. The BW and the EBW at the end of finishing phase were greatest for the HH animals, lowest for the LH and intermediate for MH that did not differ than HH and LH. The carcass weight and carcass dressing percentage were higher (P<0.05) for HH than others treatments. The HH treatment had greater (P<0.05) fat thickness. About the beef quality, at the end of growing phase significant difference (P>0.05) was observed for the final sarcomere length, with the highest average value to HH treatment, the lowest to LH and intermediate for MH that did not differ from the others two treatments. At the end of growing phase, the LH treatment showed a lower (P<0.05) redness (a*) than MH and HH treatments, that did not differ among themselves. At the end of growing phase, was found significant difference (P<0.05) for the beef yellowness (b*), the HH treatment had the highest average value, the LH treatment had the lowest and the MH had intermediate value, which did not differ from the others. At the end of finishing phase did not significant differences (P>0.05) were observed among the treatments for all evaluated beef traits. It is concluded that young Nellore cattle previously submitted to qualitative and quantitative food restriction, have higher daily gains of body components and are more efficient to convert food to carcass. Young Nellore cattle when previously submitted to qualitative restriction, exhibit complete catch up during finishing phase, without exhibit compensatory gain. Previously restricted animals have greater relative intakes of DM and fiber, higher gain of non-carcass components, lower transference from live weight gain to carcass gain, lower carcass dressing percentage and produce lighter and leaner carcasses. About the beef quality, it is concluded that dietary restriction post- weaning does not affect the beef quality after a long finishing phase. The evidences suggest that in the chilling conditions of this trial, the carcasses should be a minimum of 3.6 mm back fat thickness to prevent negative impacts of cold shortening on final sarcomere length and consequently on meat tenderness.