Desempenho e exigências nutricionais de energia e proteína para bezerros mestiços HolandêsxGir lactentes sob diferentes planos de alimentação

• Ano de defesa: 2013
• Autor(a) principal: Silva, Alex Lopes da
• Orientador(a): Marcondes, Marcos Inácio
• Banca de defesa: Chizzotti, Mario Luiz , 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: Energia; Leite; Proteína
• Palavras-chave em Inglês: Energy; Milk; Protein
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL::EXIGENCIAS NUTRICIONAIS DOS ANIMAIS
• Link de acesso: http://locus.ufv.br/handle/123456789/5786

The objective was to evaluate the intake, digestibility, nitrogen balance and performance, and determine the nutritional requirements of energy and protein for crossbred HolsteinxGir dairy calves until 60 days of life. Thirty nine crossbred dairy infant calves, uncastrated, with degree of blood varying of, approximately, 1/2 to 3/4 HolsteinxGir and average weight of 36+-0.95 kg, were used. Five animals were designed as reference group and were slaughtered at 4 days of life, to estimate initial body composition of animals kept in experiment. The other calves were distributed according to a completely randomized design in a factorial 3X2, with three levels of milk (2.4 or 8 liters/day) and two levels of starter (with or without ad libitum access to feed starter). At 15 and 45 days of life, 4 animals from each treatment were submitted to apparent digestibility trial with total collection of feces and urine, having duration of 24 hours. Food, feces and body components samples were evaluated for dry matter (DM), organic matter (OM), crude protein (CP) and ether extract (EE). Starter and feces samples were also evaluated for neutral detergent fiber corrected for ash and protein (NDFap). Urine samples were used to estimate the urinary nitro gen excretion and purine bases. Dry matter, organic matter, crude protein, ether extract, non-fibrous carbohydrates, metabolizable energy and digestible organic matter intakes increased according to the increase in milk volumes. Nutrients digestibility was higher for the high milk levels and effect of starter inclusion was not observed. Performance was higher for animals that received starter, except for hot and cold oarcass yield. And the performance was higher for animals that received large amounts of milk. Feoal nitrogen was higher for animals that received starter and was not altered for milk levels. Net energy requirement of maintenance was 70,8 koal/EBW^0,75 /day and the metabolizable energy requirements was 99,85 kcal/EBW^0,75 /day. Net energy requirement for gain, in Mcal/day, can be estimated by the equation: 0.0882 x EBW^0,75 x EBG^O,9050. Metabolizable energy efficiency for gain of a mixed diet was 51.58% and the efficiency for a diet containing only milk was 57.39%. Metabolizable protein requirement for maintenance was 3.16 g/LW^O,75. And the net protein requirements for gain, in g/day, can be estimated by the equation: 119 X EBW^O,0663. Metabolizable protein efficiency for gain was 72.9%. It can be conclude that starter dry matter intake is negatively influenced by milk dry matter intake and the performance and nitro gen retention increase according to dry matter intake. Energy efficiency for gain of milk is higher than that of the starter, and these values were 57.39 and 39.30%, respectively. Net protein requirement for gain increase following the increase in empty body weight and the metabolizable protein efficiency for gain is related to diet amino acid profile.