Ureia e sal mineral em suplementos para vacas mestiças leiteiras

• Ano de defesa: 2014
• Autor(a) principal: Teixeira, César Roberto Viana
• Orientador(a): Lana, Rogério de Paula
• Banca de defesa: Zamperlini, Belmiro , Veloso, Cristina Mattos , Silva, José Carlos Peixoto Modesto da , Rennó, Luciana Navajas
• 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: Bovino de Leite - Alimentações e rações; Leite - Produção; Ureia; Suplementos para bovinos
• Palavras-chave em Inglês: Dairy Cattle - Feeds and feed; Milk - Production; Urea; Supplements for cattle
• 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/123456789/5814

This study aimed to evaluate the use of supplements with different proportions of urea and mineral salt, for dairy crossbred cows fed with sugarcane on intake and digestibility of dry matter (DMI and DMD respectively) and its constituents ,milk production and composition, feed efficiency , excretion of nitrogenous compounds and microbial protein synthesis . Ten crossbred cows with average body weight of 480 kg (± 30) were used after lactation peak, distributed in a 5x5 Latin square design, duplicate, with four treatments of supplements with different percentages of urea and mineral salt, being these: 10:10; 10:20, 20:10 and 20:20, completed to 100% with corn meal, beyond the fifth treatment consisting only of mineral salt. The experiment lasted 14 days each, with the first seven days for adaptation and the other to collect data and samples. Data were analyzed using the MIXED procedure of SAS, adopting a significance level of 0.05. The use of supplements provided increased (P < 0.05) in total DMI, sugarcane, supplement and all constituents of DM. In percent of DM intake, supplementation increased the level of organic matter (OM), crude protein (CP) and non-fibrous carbohydrates (NFC) and decreased of neutral detergent fiber digestibility (NDFD). The increase of urea level in supplements caused lower DMI of supplement, total, OM and NFC, but increased the levels of OM, CP, NDFD, decreasing only content NFC. With the increase in the proportion of mineral salt in the composition of supplements decreased (P < 0.05) levels of OM and CP in the diet. The use of supplements increased (P < 0.05) the digestibility of DM, OM, CP and NFC and daily intake of DM, OM, CP, EE, NDFD and NFC digestible and, consequently, total digestible nutrients (TDN) and digestible energy consumed. The increased level of urea in supplements decreased (P < 0.05) consumption of DM, OM, EE and NFC digestible. The increased level of mineral salt did not change the parameters of digestibility and intake of digestible nutrients. The use of supplements resulted in maintenance of animals body weight, unlike the control diet, which was daily loss (P < 0.05) from 0.95 kg/day. The treatments with the presence of supplements showed higher (P < 0.05) milk production. Milk composition did not change (P> 0.05) for the diet. The use of supplements resulted in fewer values (P < 0.05) of somatic cell count (SCC) and total bacterial count (TBC) in milk. Supplements, when compared to control or mineral salt (0:100) had (P < 0.05) lower gCP/kgTDN ratio and increased urea nitrogen excretion in urine, blood plasma and milk. The increased level of mineral salt practically did not change the parameters of daily excretion of purine derivatives, microbial N compounds and concentrations of urea nitrogen, except to urinary nitrogen urea that reduced. Supplements can be used to correct nutritional deficiencies of sugarcane, resulting in increased intake, digestibility and milk production. Supplements with 20% urea (20:10 e 20:20) in its composition resulted in lower consumption with the same animal performance and can be concluded that these treatments showed better utilization efficiency.