Dietary replacement of soybean meal with lipid matrix-encapsulated urea does not modify milk production and composition in dairy goats

This study evaluated the performance and quality of milk from dairy goats supplemented with urea protected into lipids matrix microencapsulation for controlled release replacing soybean meal. Eight crossbred Alpine dairy goats, multiparous, with an average lactation stage of 70 ± 5.0 days after calving were distributed in a double latin square design was used with four treatments [SBM = control, soybean meal as nitrogen (N) source; microencapasulated urea using beeswax (BWUME), carnauba wax (CWUME) and vegetable fat (VFUME) as encapsulants], replacing soybean meal at 25 % in goat diets. The BWUME replacing SBM protein improved (P ≤ 0.05) intake of CP, N-total, nitrogen insoluble in acid detergent (NIAD), and EE also improved milk production4% corrected, solids-corrected milk, protein, fat, total solids and defatted dry extract and feeding conversion comparing other microencapsulated systems. BWUME and CWUME presented greater (P ≤ 0.05) crude ash, nitrogen insoluble in neutral detergent (NIND) and NDFap intakes compared to VFUME and SBM. The CWUME and VFUME presented greater and lower DMI and crude energy intakes, respectively comparing to other microencapsulated systems and SBM. The TC and NFC intake were greater (P ≤ 0.05) in SBM and VFUME, and lower for BWUME. The SBM presented greater milk production, lower fat and total solids contents compared to other microencapsulated systems. Hematological parameters and serum protein in goats did not differ among treatments. However, at ½ hour before and 1:30 h (P = 0.023) after feeding, the goats receiving BWUME presented greater (P ≤ 0.05) blood urea nitrogen (BUN) comparing to other diets. At 3:00 h after feeding, the BUN concentrations of the all microencapsulated urea formulations were higher que SBM (P = 0.011). The BWUME inclusion for controlled release replacing 25 % SBM promoted similar milk production, solids content and feeding conversion, as well as greater CP intake, N-intake and fat milk concentration in dairy goats.