Ureia protegida com diferentes encapsulantes lipídicos para liberação controlada em dieta de cabras em lactação.

Abstract

The non-protein nitrogen available from urea is used to supply the protein requirements of animals. However, there is a problem of urea poisoning, which limits the use of this ingredient in diets provided to animals. Thus, the objective of this study was to evaluate the effects promoted by the insertion of protected urea with different lipid encapsulants (hydrogenated fat, beeswax and carnauba wax) on the performance and serum levels of dairy goats in Brazilian semiarid region. Four multiparous Alpine crossbred dairy goats, with an average lactation stage of 70 ± 5.0 days after calving, kept in confinement, allocated in individual pens partially covered with fiber cement roof, with free access to water and fed ad libitum. The experimental trial was arranged in a Latin square (4x4), where the square consisted of four animals, four treatments and four 13-day periods (10 days for adaptation to facilities and diets, and three days for data collection). The treatments were as follows: T1 = control, corresponding to a single source of nitrogen from soybean meal, T2, T3 and T4 where beeswax, carnauba wax and hydrogenated fat encapsulated urea were used, respectively. The proportion of partial replacement of soybean meal by encapsulated urea was 75% of soybean meal and 25% of encapsulated. The source of roughage was corn silage, and the source of concentrate was corn and soybean meal and mineral salt. It was observed that the use of urea encapsulated with hydrogenated fat, beeswax and carnauba wax, in partial replacement to soybean meal crude protein in the diet of lactating goats, did not influence the dry matter intake and feed conversion. However, altered consumption of some nutrients such as neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen. In addition, the use of encapsulated urea did not affect milk production and physiological parameters of animals. It was also observed that the inclusion of encapsulated urea in the animals' diet did not affect their health, since they did not show clinical and metabolic signs of urea poisoning. Therefore, the lipid encapsulants tested in this research are effective for the gradual release of nonprotein nitrogen.