Exigências líquidas de proteína, energia, cálcio e fósforo para ovinos em crescimento em clima semiárido.

Abstract

This work aimed to estimate the nutritional requirements of protein, energy, calcium and phosphorus for weight gain of Santa Inês sheep with different genders. The experiment was carried out at the Research Center for the semiarid region (NUPEÁRIDO), Federal University of Campina Grande (UFCG), Patos-PB. Twenty-four 80˃5 day-old sheep were used, including 12 males and 12 females, with an average body weight (BW) of 15 Kg. The effect of 0%, 25% and 50% of food restriction was analyzed to both genders. The diet consisted of elephant grass hay and concentrate with a ratio of 50:50 (roughage:concentrate), in a confinement system. The body composition per Kg of the sheep varied from 285.98 to 320.16 g of dry matter, 41.60 to 46.96 g of mineral matter, 60.97 to 83.93 g of fat, 160.44 to 175.71 g of protein, 1.49 to 1.80 Kcal of energy, 8.71 to 9.83 g of calcium and 7.01 to 7.81 g of phosphorus per Kg of BW. The protein concentration in the animal body increased from 152 to 182 g/Kg (P<0.01) when the animals' weight increased from 15 to 30 Kg. The energy content per Kg of empty body weight gain (EBW) ranged from 2.21 to 3.39 Mcal. Estimates of body composition as a function of EBW for calcium and phosphorus increased from 97 to 203 g and from 94 to 175 g*Kg-1, respectively, as body weight increased from 15 to 30 Kg. The net requirements of protein and energy were similar for both genders to all analyzed variables (Pޓ0.05). The values observed in this study were lower than those recommended by international systems. Net protein and energy requirements were similar for both males and females and increased with increasing body weight. The estimate of protein requirements was similar to that presented in the National Research Council (NRC), while energy was 27% lower.