Consumo, digestibilidade, parâmetros ruminais e desempenho de bovinos de corte suplementados com dietas contendo silagens de diferentes híbridos de sorgo

• Ano de defesa: 2007
• Autor(a) principal: Cezário, Andréia Santos
• Orientador(a): Pereira, Odilon Gomes
• Banca de defesa: Ribeiro, Karina Guimarães , Paulino, Mário Fonseca
• 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: Forragem; Conservação; Compostos nitrogenados; Ganho de peso; Bovino de corte
• Palavras-chave em Inglês: Forrage; Conservation; Nitrogen composts; Weight gain; Beef cattle
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PASTAGEM E FORRAGICULTURA
• Link de acesso: http://locus.ufv.br/handle/123456789/5553

Two experiments were carried out at the Central de Experimentação, Pesquisa e Extensão do Triângulo Mineiro CEPET, Capinópolis-MG, from July to November 2005. In the first experiment, the following variables were evaluated: intakes, total apparent digestibilities of the nutrients, the pH, the ruminal ammonia concentration, the efficiency of the microbial synthesis, the degradation kinetics and the effective degradability (DE) of either dry matter (MS) and fiber in neutral detergent (FDN) in crossbred beef cattle Holstein x Zebu fed diets containing silages of four sorghum hybrids (1F305, XBF60329, BRS610, Volumax) and concentrate at 70:30 proportion, based on the dry matter. Four castrated, rumen and abomasum fistulated steers with 400kg average live weight were distributed into 4x4 square lattice design. Each experimental period lasted 17 days, as being 10 days for adaptation to the diets and seven for collecting the data. The chromic oxide was used to estimate both the fecal and abomasal dry matter flows, and the microbial efficiency was determined with urine purine bases. The pH and ruminal ammonia were measured before, and 3 and 6 hours after feeding. Two rumen-cannulated Holstein x Zebu steers were used for evaluation of the ruminal degradability. Approximately 3g pre-dried sample of the respective silages were conditioned into each nylon bag, at duplicate for each incubation time (0, 3, 6, 12, 24, 48, 72, 96, 120 and 144 hours). The intake of the dry matter (MS), organic matter (MO), crude protein (PB), ethereal extract (EE), total carbohydrates (TC) and total digestible nutrients (TDN) were not affected (P>.05) by diets, neither the total apparent and the ruminal and intestinal digestibilities, except for the total apparent digestibility of NDF that was lower (P <.05) for the hybrid BRS610. The ammonia concentration and the ruminal pH were not affected by the collection times nor by diets and their interactions, as registering average values of 13.0 mg/100ml and 6.49, respectively. The efficiency of the microbial synthesis was not influenced by the diets, as the values 169.6, 155.2, 153.5, 154.6g PBmic/100gNDT were obtained for those animals feed diets containing silage of the hybrids 1F305, XBF60329, BRS610 and Volumax, respectively. Concerning to degradability, the silage of the hybrid XBF60309 showed the lowest values for both fractions "a" and "b" relative to MS. Concerning to the ruminal degradability of FDN, the B fraction showed lower values for BRS610. The silage of the Volumax hybrid showed the lowest non-degradable fraction I (20.8%). In the second experiment, the following were evaluated: the intake and the total apparent digestibility of the nutrients, the average weight gains, feed conversion and carcass yield in beef cattle given same diets as the previous assay. Twenty eight castrated and crossbred beef cattle Holstein x Zebu with 370Kg initial weight and 20mos. age, distributed into randomized block experimental design, with four treatments and seven replicates. The intake of MS, MO, PB and NDT were not affect affected by the diets, as the average values 9.65, 9.08, 1.03, 5.71 Kg/day were respectively registered, whereas the intake of the neutral detergent fiber (FDN) was lower (P <.05) in the diet containing silage of the hybrid BRS610. The apparent digestibilities of MS, MO, PB, EE, FDN, CNF and CHOS were not affected by the diets, as the average values 57.7, 63.2, 58.5, 67.3, 54.4, 78.0 and 63.3 were respectively registered. Also, the weight gains and feed conversion were not influenced by the diets. Those diets are nutritionally equivalent, since they promoted similar animal performance, without affectivy the ruminal fermentation.