On farm evaluation of the energy levels in the diet on the production and physical-chemical composition of dairy goats

The objective of this study was to evaluate the effect of diets with different energy levels on nutrient intake, milk production and composition, body weight and benefit:cost ratio of a dairy goat production. Nine goats were distributed in a triple 3 x 3 latin square design. The experiment lasted for 60 days, divided into three 20-day periods. Complete rations containing three energy levels were evaluated: 65%, 70% and 75% of TDN. The dry matter intake, crude protein and mineral matter consumption were higher (P <0.05) in the diets with higher levels of energy compared to the diet with 65% of TDN. Milk production was similar (P> 0.05) in goats receiving diets containing 70% and 75% TDN, but these diets produced more milk (P<0. 05) than the diet with 65% of TDN. The diet with 75% of TDN allowed a higher (P<0.05) final body weight (P<0.05) when compared to diets containing 65% and 70% TDN. There was no difference (P> 0.05) in the physical-chemical parameters of fat, lactose, crude protein, defatted dry extract, density, salts and conductivity of the milk. Therefore, goats fed with diets of 70% and 75% of TDN in the total diet increased milk production. However, the diet with 75% of TDN provides a better benefit:cost ratio, as for every $ 1.00 in the cost invested, there was $ 1.52 of financial return.