Total Replacement of Millet Silage with BRS-716 Biomass Sorghum Silage in Crossbred Dairy Heifers Diets: Nutrient Intake and Digestibility, Microbial Protein Synthesis, Ingestive Behavior, and Growth Performance

Abstract This study addressed the different proportions of millet and sorghum silage biomass BRS 716 (BRS-716 silage) in the diet of crossbred heifers ½ to ¾ Holstein x Zebu on their nutrient intake, and digestibility, microbial protein synthesis, nitrogen balance, ingestive behavior, and growth performance. Five experimental diets with 0, 25/75, 50/50, 75/25, and 100% of BRS-716 silage in compared to millet silage were evaluated. The roughage: concentrate ratio in the total dry matter (DM) of the diets was 75:25. The diets were evaluated in ten heifers with an initial body weight of 264.95 ± 19.4 kg (± SEM), following the experimental design in two 5 x 5 Latin squares, simultaneously. The increase in the proportion of BRS-716 silage in the diet of crossbred dairy heifers did not change the dry matter intake (DMI), total digestible nutrients, indigestible neutral detergent fiber (iNDFI), and metabolizable energy. The means observed for DMI, and iNDFI were 7.85 kg/day, and 1.18 kg/day, respectively. For the excretion of purine derivatives, and microbial synthesis, there was no significant effect (P > 0.05), the mean microbial crude protein synthesis was 503.37 g/day. The different proportions of the BRS-716 silage, and millet silage did not change the final body weight (P = 0.89), weight gain (P = 0.08), feed efficiency (P = 0.50), and the body measurements of heifers (P > 0.05). The final body weight and average daily gain of heifers were 278.46 kg, and 0.795 kg/day, respectively. The millet silage, and BRS-716 silage in the diet of crossbred Holstein x Zebu heifers, used exclusively or combined in different proportions, allow dry matter intake, and nutrients, digestibility, nitrogen balance, microbial crude protein synthesis, ingestive behavior, and performance similar body.