BIOECONOMICAL EVALUATION OF FOUR BEEF PRODUCTION SYSTEMS BASED ON PASTURE ENERGY-PROTEIN SUPPLEMENTATION AND INTAKE AND GROWTH STIMULANTS.

Abstract

It was used 12 Santa Gertrudis steers with ages between 14 to 16 months in order to evaluate bioeconomically four pasture beef production system and protein-energy supplementation with or without intake and growth stimulants. Four hectares of Brachiaria humidicola (70%) plus Brachiaria decumbens (20%) and Digitaria swazilandensis (10%) were utilized. Pastures were fertilized with 60, 30, 20 kg/ha/year of N, P₂O₅ and k₂O. The beef production systems were: (T1) pasture + supplementation; (T2) T1 + implants; (T3) T1 + inophores (Sodic Lasalocid); (T4): T1 + implants + inophores. Supplementation consisted of 0.9, 0.09 and 0.045 kg DM/100 kg LV/d of molasses, fish meal and urea, respectively. T2 and T4 system were used two implants (day 15 and day 90) compound of 200 mg Progesterone + 20 mg Estradiol Benzoate. A health plan was implemented to control internal and external parasities. Animals were weighted periodically and pasture samples were taken at random during each rotation. Live weight data were analyzed by regression and covariance techniques. Non adjusted daily body weight change and live body weight were to T1, T2, T3 and T4 were: 0.787, 0.897, 0.851 and 0.947 kg, respectively, and 439, 459, 438 and 476 kg, respectively. General average dressing percentage was 58%. The 5.0 g of Sodic Lasalocid did not reduce Coccidias charge, but stimulated daily body weight gain. Strongylus and Strongyloides parasites were little above of 200 epgf. Initial and final stocking rate were 2.09 and 3.39 AU/ha, respectively. Feeding costs represented 14.0% to 15.5% of the variable costs. Daily cost of the liquid mixture varied from $0.226 to $0.325. It was concluded that is economically feasible increase beef production with systems based on pastures with energy-protein supplementation, inophores and implants.