Fontes de proteína para vacas em lactação

• Ano de defesa: 2005
• Autor(a) principal: Pina, Douglas dos Santos
• Orientador(a): Valadares Filho, Sebastião de Campos
• Banca de defesa: Valadares, Rilene Ferreira Diniz , Campos, José Maurício de Souza , Detmann, Edenio , Leão, Maria Ignez
• 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: Uréia; Farelo de soja; Farelo de algodão; Leite; Nutrição animal; Ruminantes
• Palavras-chave em Inglês: Dairy cattle; Urea; Soybean meal; Cotton meal; Milk; Animal nutrition
• 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/123456789/5678

Twelve Holstein and cross-bred dairy cows were used in this trial and were distributed in a three latin square design (4x4), according to days in milk, aiming at evaluate the effect of two periods of fecal collection was also evaluated (two or six days) in 26 hours intervals. The effect of two markers (insoluble neutral detergent fiber (NDFi) or insoluble acid detergent fiber indigestible (ADFi)) and of the diets with differents protein sources on intake, nutrients digestibility, milk production and composition, on efficiency of microbial protein synthesis, calculated by urinary excretion of purine derivatives, plasma (PUN) and milk (MUN) urea nitrogen concentration, ruminal ammonia concentration and pH. The A corn silage based diet (60% of the total dry matter) was used and the concentrate was formulated with different proteins sources (SM soybean meal, CM38 cottonseed meal with 38% of crude protein, CM28 - cottonseed meal with 28% of crude protein and SMU soybean meal plus 5% of urea/ammonium sulfate in the concentrate dry matter). The four experimental periods lasted 18 days each, being the last seven days used to sample collections. Milk samples from each animal were collected twice (morning and afternoon) at the 15th day of each experimental period, and later were combined in order to obtain a composed sample. Urine (spot) and blood collections were accomplished at the 18th day of each experimental period, at approximately four hours after the morning feeding of the animals. The urinary volume (V) was estimated using 24,4mg/kg live weight of creatinine as a daily mean. The means comparisons were always made in relation to the control diet (SM). Dry matter (DMI) and organic matter intakes (OMI) didn't differ among diets (P>0,05), whereas crude protein (CP) intake was larger to the CM38 diet. Rumen degradable (RDP) and undegradable protein intakes (RUP) were larger and smaller, respectively, to the CM28 and SMU diets. The intake of ether extract were larger to the CM28 and SMU diet and smaller to the CM28 diet, whereas non-fiber carbohydrates (NFC) and neutral detergent fiber (NDF) intakes were smaller and larger, respectively, to the CM38 and CM28 diets. Total digestible nutrients (TDN) intake was smaller (P <0,05) in both diets, when compared to the control diet (SM). The fecal dry matter excretion (FDME) was overestimated and the digestibility coefficients of DM, OM, CP, NDF and NFC were underestimated by ADFi, but .fecal collection days had no effect on the estimates. The DM, OM and NDF digestibility coefficients (DC) were smaller (P <0,05) in the CM38, CM28 and FSU diets compared to the control diet. CP and EE digestibility were smaller and larger (P <0,05), respectively, in the CM38, CM28 diets, while NFC digestibility was smaller (P <0,05) in the SMU diet. Milk yield (MY), corrected or not for 3,5% of fat, milk fat concentration and production were not influenced (P <0,05) by the different protein sources, albeit DM and nitrogen efficiency of use for milk production, milk protein concentration and production were lower (P <0,05) in the diets formulated with cottonseed meal to the diet formulated with SM. Differences among diets for urinary volume (V), total excretion of purine derivatives (PT), microbial CP synthesis and efficiency of synthesis, expressed in g of CP/kg of intake TDN, were also not detected. PUN and MUN concentrations did not differed (P>0,05) among the diets. It was concluded that two days of fecal collection were enough to estimate FDME and to obtain the nutrients digestibilities and the contents of TDN of the diets and that NDFi was the most precise marker than AFDi. Also it was concluded that dairy cows producing, on average, 25 kg/day, can be fed with diets containing 5% of urea in the dry matter of the concentrate or cottonseed meal with 38% CP, in situations where the roughage is composed by 60% (total dry matter basis) of corn silage.