Consumption and apparent digestibility of dairy cows fed with enzymes

Abstract

The project aims verify if the inclusion of exogenous enzyme fibrolytic improves fiber digestion and enhances the reply to the addition of amylolytic enzymes, about the apparent total digestibility of dry matter and nutrients and productive performance. For the experiment, will be used eight Holstein cows, multiparous and cannulated's rumen, that will be distributed in two latin squares 4x4, allocated in groups based on milk production, days in lactation and body weight at the beginning of experiment. Will be done four treatments: CON (basal diet without enzyme supply), EF (addition of 12 g / d of fibrolytic enzyme), EA (addition of 8 g / d of amylolytic enzyme) and EF * A (addition of 12 g / 8 g / d and fibrolytic amylolytic enzyme, respectively). The samples of food, remains and stools will be analyzed about the content of dry matter (DM), crude protein (CP), ether extract (EE), acid detergent fiber (ADF) and lignin, and neutral detergent fiber (NDF); the concentration of digestible total nutrients and of net energy diet lactation will be calculated according methodology of NRC (2001) and the diet samples offered and the remains will be analyzed about the particle size, for calculate the selection index. The total apparent digestibility will be obtained by the difference between the observed consumption and estimated fecal excretion of dry matter and nutrients, the production will be measured daily, and will be defined the crude protein, fat and lactose, and concentrations of urea, allantoin and uric acid. The data obtained will be submitted to variance analysis by PROC MIXED, using the SAS program. (AU)