Produção e composição do leite de cabras saanen alimentadas com diferentes carboidratos associados à ureia

Abstract

The goal of this study was to evaluate the impact of diets composed of different carbohydrates sources associated with urea, on the milk production and composition, as the milk fatty acids profile from lactating Sannen goat, as well as the effect of these diets on dry matter intake, digestibility and estimation of digestible fractions, cumulative gas production and food degradation rates. Four sorts of diet combinations were tested, with Tifton 85 hay as forage source for all of their, and combinations of soybean meal and corn (FSMi), corn and urea (MiUr), cassava chips and urea (RMUr) and cactus pear and urea (PMUr). Twelve lactating multiparous goats, with average body weight of 50 kg and daily milk production of 2.0 kg were used in the study, which had the experimental design in latin square, and the lactation order as the criterion for squares formation. The means were compared by the Tukey test, considering P<0.05. The dry matter intake did not differ statistically, however the FSMi treatment presented higher intake for most of the nutrients. The mean crude protein intake for treatments was higher than the calculated requirement. The treatments MiUr and RMUr presented higher results for the non-fibrous carbohydrates intake. The non-fibrous carbohydrate content digestibility was not statistically different (P> 0.05), whereas for the crude protein digestibility, the treatments MiUr, RMUr and PMUr were highlighted. Considering food digestible fractions, the soluble fraction was greater in the cassava chips while the corn has higher content of the fraction potentially degradable. The RMUr treatment presented higher cumulative gas production than the other treatments. Regarding the milk evaluation, the results of dry matter intake, milk production and milk production corrected to 3.5% of fat did not present statistical difference among them, as did others milk compounds such as protein, fat, lactose, total solids, casein, non-fat solids and milk urea nitrogen. Milk temperature and pH presented no statistical difference (P> 0.05), the opposite was observed for milk acidity, density and cryoscopic index. The atherogenicity index was higher for the treatments MiUr and RMUr and the enzyme Δ9 desaturase activity was considered higher in the treatments FSMi and MiUr.