Protein-energy supplementation on productive and nutritional performance of grazing beef heifers

This study was conducted with the aim of evaluating effect protein-energy supplementation on productive performance, intake, digestibility, and microbial protein synthesis in heifers fed tropical forage. Twelve Nellore at 11 months age, a mean initial body weight 248.8 ± 11.40 kg were used. The animals distributed completely randomized design two treatments six replicates. evaluated were: control (without supplementation); amount 1.5 animal-1 day-1. Forage samples collected to evaluate chemical composition total availability dry matter pasture consumed by animals. To intake forage trial performed using internal external markers. In this no observed intakes (DM), organic (OM), DM, or neutral detergent fiber corrected for ash (NDFap; P > 0.10). However, increased (P < 0.01) crude (CP), ether extract (EE), non-fibrous carbohydrates (NFC). Additionally, an upward trend (P=0.076) digested OM (DOM) supplementation. On other hand, digestibility coefficients OM, CP, EE, NFC, although did not affect ruminal nitrogen compounds (MICN), efficiency (EMS), relative (RMICN) urine urea (UUN) excretion 0.57). Lastly, (P=0.050) average daily gain animals, 0.10) their final weight. These results suggested that improves performance nutritional characteristics grazing beef heifers.