MINERAL, PROTEIN, AND ENERGY SUPPLEMENTATION IN HEIFERS IN A NATIVE PAMPA BIOME PASTURE DURING WINTER

This study evaluated the effect of different supplements during winter on the performance of heifers in a native Pampa biome field using deferred grazing and evaluated the economic viability of each treatment. A total of 124 heifers from Brangus and Angus breeds, 18 months old, and with an average weight of 301.6 kg were included in this experiment. The treatments applied were: control with only native grassland, native grassland + 80P mineral salt treatment (MS), native grassland + protein salt treatment (PS), and native grassland + protein/energy salt treatment (PES). Besides the productive, botanical, and bromatological characteristics of the pasture, the average daily gain and the live weight gain per hectare were evaluated. The economic viability of the treatments was evaluated through partial budgeting. Weight loss was observed in all treatments. However, only the PES treatment differed from the others, with an average daily gain of -0.046 kg dia -1 (p value < 0.005). The MS treatment was the best regarding economic viability. Despite that, the smallest weight loss was observed in the PES treatment, which may be a determinant in the development and future performance of heifers. Despite the small net margin, this treatment did not incur additional costs to the system.