Desempenho e exigências de energia e proteína de bovinos Nelore estratificados por consumo alimentar residual

• Ano de defesa: 2011
• Autor(a) principal: Araújo, Fabiana Lana de
• Orientador(a): Queiroz, Augusto César de
• Banca de defesa: Detmann, Edenio , Chizzotti, Mario Luiz , Silva, Márcia Maria Cândido da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Alimentação; Consumo alimentar
• Palavras-chave em Inglês: Feeding; Feed intake
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL::AVALIACAO DE ALIMENTOS PARA ANIMAIS
• Link de acesso: http://locus.ufv.br/handle/123456789/1846

Two experiments were conducted involving 40 comparative slaughter Nellore steers stratified by residual feed intake with body weight of 413 kg and an average age of 18 months, to determine the net requirements of energy and protein for maintenance and weight gain. Nine animals were slaughtered at the beginning of the experiment to determine initial body composition. The remaining animals were randomly allocated in two levels of feed: fed ad libitum and restricted feeding (65 g DM/kg BW) containing 80% of dry matter from the concentrate diet and 20% of dry matter from the Brachiariabrizantha hay. The diets of the two experiments were calculated to be isocaloric and isonitrogenous. Each experimental period was 112 days, and the animals were destined for slaughter when they reached 4 mm thick fat. The empty digestive tract, organs, carcass, head, leather, tail, feet, blood and other tissues were weighed to determine the empty body weight (EBW). After being sawn into smaller pieces and have been frozen parts were ground separately, mixed and sampled for the chemical analyzes. The dry matter intake was measured daily and individually. Data relating to the carcass, organs and viscera weight gain, empty body weight (EBW), average daily gain (ADG), dry matter intake (DM), mineral matter (MM), crude protein (CP), extract ether (EE), neutral detergent fiber (NDF), non-fiber carbohydrates (NFC), total digestible nutrients (TDN) yield primary cuts, proportion of edible fractions, bones and trimmings. To calculate the requirements we used the antilog of the intercept of the linear regression of log heat production (PC) with energy intake (CEM) to estimate the net energy requirement for maintenance (NEm, kcal/kg PCVZ0,75/day). The metabolizable energy requirement for maintenance was achieved with the aid of the interactive method, assuming that the application for maintenance is the point where the EMF equals the equation𝑃𝐶 = 𝛽0 ∗ 𝑒𝛽1∗𝐶𝐸𝑀 . The slope of the regression equation of retained energy in CEM was adopted as the efficiency of utilization of metabolizable energy for gain (kg). Alternatively, kilograms divided by the intercept was used to calculate the metabolizable energy requirement for maintenance. The requirement of metabolizable protein for maintenance was calculated from the equation CPMetm = β0 + β1 ∗ PV, whereβ0 = estimation of requirement of metabolizable protein for maintenance (PMetm);β1= efficiency of utilization of metabolizable energy for gain and BW = body weight (kg). The data relating to consumption, performance and carcass composition and carcass were not analyzed according to a completely randomized design in a factorial 2x2x2. The nutritional requirements of energy and protein were analyzed using a random model considering the effect of the experiment as a random effect and the level of supply and CAR group as fixed effects. Observed difference in dry matter intake and other dietary nutrients between different groups CAR, already with regard to animal performance and carcass composition and carcass there was no difference in the level of supply. There was no difference in the energy requirements for maintenance and energy requirement for gain between the different groups of CAR. The protein requirement for maintenance also no significant differences between groups for CAR as well as protein requirements for weight gain.