Grão de soja cru e integral na alimentação de vacas leiteiras

Abstract

BARLETTA, R. V. Whole and raw soybean in feeding of dairy cows. [Grao de soja cru e integral na alimentacao de vacas leiteiras]. 2010. 96 f. Dissertacao (Mestrado em Ciencias) – Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, Pirassununga, 2010. This study was conducted to evaluate the effects of different levels of inclusion of crude soybean and full in feeding of dairy cows in early lactation and their effects on intake and dry matter digestibility and nutrients, rumen fermentation, microbial protein synthesis, yield and milk composition, fatty acids profile of milk fat, concentrations of blood parameters, energy and nitrogen balance, excretion and composition of soybean present in faeces and productive performance. A total of 12 holstein cows, grouped in three latin squares balanced and contemporary 4x4, fed the following diets: 1) control (C), composed of feed without the inclusion of soybean, 2) grain soybean 8% (G8), 3) grain soybean 16% (G16), and 4) grain of soybean 24% (G24), using respectively 8.0, 16.0 and 24% of whole raw soybean in the diet, in dry matter. Milk yield and dry matter intake were measured daily throughout the experimental period. The samples used for analysis of milk composition were collected on the 16 day of each period, and from the two milkings. Blood samples were collected in tubes by venipuncture vacuolated and/or coccygeal artery. Samples of rumen fluid were collected with use of gavage three hours after the morning feeding. The digestibility was determined by means of an internal indicator iADF. A reduction in dry matter intake and non-fibrous carbohydrates in cows fed the G24 ration compared to other diets, which did not differ. Increased linear effect was observed in the ether extract intake in the consumption of fat, where the animals submitted to G24 diet presented higher values. Total apparent digestibility of the nutrients between experimental diets, and the G24 diet showed decreased crude protein digestibility compared to diets C, G8 and G16. No effect of diets used in the values of rumen pH. The rumen ammonia concentration was higher (P<0.05) for cows that received the control diet compared to diets with soybean. Among the rations, ration G24 resulted in decreased milk yield and protein in Kg/day. The levels in milk protein, fat and lactose were not affected by fat sources added to the diet, just as the fatty acid profile of milk fat did not significantly change. The concentrations of total cholesterol and HDL were higher for cows fed diets containing soybean in relation to the control diet. The urea and urea nitrogen concentrations in serum and milk were similar between the rations. The rations did not affect microbial protein synthesis. The energy balance was not influenced by experimental diets. There was an effect of experimental diets on nitrogen balance, where the G16 ration presented better result, and fecal nitrogen excretion was higher for G24 diet. Regarding the composition of faeces G24 diet showed larger percentages of protein and fat, and excretion of soybean in the feces showed a increasing linear effect, as well as the increased levels of inclusion of grain increased excretion in the faeces. The use of different levels of soybean in the diet alter the intake, productive performance and metabolism in dairy cows, and the results being dependent on the stage of the level of raw and integral soybean added to diets. Key-words: Dairy Cows, Whole Soybean, Milk yield and composition, Digestibility, Blood parameters LISTA DE ABREVIACOES E SIGLAS AG Acidos Graxos AGL Acidos Graxos Livres AGPI Acidos Graxos Poliinsaturados AST Aspartato Aminotranferase BE Balanco de Energia BN Balanco de Nitrogenio CD Coeficiente de Digestibilidade CED Consumo de Energia Digestivel CEL Consumo de Energia Liquida CLA Acido Linoleico Conjugado CMS Consumo de Materia Seca CT Carboidratos Totais DAT Digestibilidade Aparente Total DP Derivados de Purina ED Energia Digestivel EE Extrato Etereo ELg Energia Liquida de Ganho ELL Energia Liquida de Lactacao EM Energia Metabolizavel EUA Estados Unidos da America FA Fosfatase Alcalina FDA Fibra em Detergente Acido FDN Fibra em Detergente Neutro FS Farelo de Soja GGT Gama Glutamiltranferase GS Grao de Soja GSI Grao de Soja Integral HDL Lipoproteina de Alta Densidade JDS Journal of Dairy Science MN Materia Natural MO Materia Orgânica MPCV Movimentacao de Peso de Corpo Vazio MS Materia Seca Nmic Nitrogenio Microbiano N-NH3 Nitrogenio Amoniacal Pabs Purinas Absorviveis PB Proteina Bruta PDR Proteina Degradavel no Rumen pH Potencial Hidrogenionico PLC Producao de Leite Corrigida PNDR Proteina Nao Degradavel no Rumen PV Peso Vivo RBZ Revista Brasileira de Zootecnia SM Silagem de Milho TRM Misturador Total de Racoes