Desempenho de bovinos superprecoces não castrados ou castrados em diferentes idades criados no sistema pasto/suplemento

• Ano de defesa: 2010
• Autor(a) principal: Rocha, Anilza Andréia da
• Orientador(a): Paulino, Mário Fonseca
• Banca de defesa: Paulino, Pedro Veiga Rodrigues , Valadares Filho, Sebastião de Campos , Valadares, Rilene Ferreira Diniz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Ruminantes; Consumo; Rendimento; Carcaça
• Palavras-chave em Inglês: Ruminants; Intake; Income; Carcass
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/5655

This work was developed in two chapters. The objective of the study described in the first chapter was to evaluate the performance nutritional and carcass traits of grazing young bulls castrate at different ages or not, supplemented or not. Fourty seven crossbred Nellore young bulls with initial age of 120 ± 30,1 were used, housed in paddocks of Brachiaria decumbens Stapf. The animals were distributed randomly in a factorial arrangement with four ages of castration and two supplementation systems. The pastures were evaluated every 28 days. The prediction of intake and digestibility used the indicators: LIPE®, titanium dioxide and neutral detergent fiber indigestible. Urine and blood samples were collected too. The concentrate supplementation improved the utilization of pasture, despite it caused a substitutive effect at all seasons evaluated. Castration of animals around the weaning time, at the beggining of the dry season hindered the animal development for, at least, six months after that castration. The trial described in the second chapter had the objective to evaluate the carcass characteristics and estimate the energy, protein and macrominerals requirements of supplemented crossbreds bulls in grazing Brachiaria decumbens Stapf. pasture, castrade at different ages or not castrade, and supplemented or not. Fourty seven young bulls with average initial age of 120 ± 30,1 days. Four animals were slaughtered as reference at the beginning of the experiment. To estimate the net energy requirements for weight gain were adjusted a equation regressing the retained energy by the empty body weight gain and the metabolic empty body weight. To estimate the net protein requirements for weight gain, were adjusted a equation regressing the retained protein by the empty body weight gain and the energy contend of this gain. The net requirements of Ca, P, Mg and Na for weight gain were determined by the equation Y’ = b. a . Xb-1, where a and b represent the intercept and the regression coefficient, respectively. The castration or the supplementation did not affected the body weigt gain requirements.