The voluntary dry matter intake (DMI), rate of passage and mean retention time in the rumen and gastrointestinal tract were estimated using 18 crossbred Holstein-Zebu lactating cows grazing elephantgrass. The voluntary DMI and fecal output estimations the models proposed by QUIROZ et al. (1988) and POND et al. (1989) were used. The data of rate of passage and those of retention time in the rumen the model suggested by GROVUM and WILLIAMS (1973) was chosen. The elephantgrass pasture were fertilized […]

The objectives of the present work were to estimate the microbial protein production using the total purine derivatives (PD) excretion, to compare the PD and the urea excretions, obtained from spot urine collection with that observed in the 24 hours collection and to evaluate the plasma and milk N-urea and urea urinary excretion. Sixteen Holstein lactating cows were assigned to four 4X4 Latin Square with 3-wk periods in accordance with the lactation period. The four experimental isoproteic diets were formulated […]

The objective of this research were to detect how many days where necessary to animals to adapt to diets, to measure intake and milk production; also, to evaluate the effect of four levels of crude protein in the non protein nitrogen (NPN) based compounds (2,22; 4,18; 5,96 e 8,09%) on the milk composition and production, the intake and apparent digestibilities of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), ether extract (EE), total carbohydrates (CHOT) and crude protein […]