Exigências Nutricionais de Caprinos da Raça Alpina em Crescimento. 1. Exigência Nutricional de Fósforo para Mantença: Perdas Endógenas e Abate Comparativo

Abstract

The objective of this experiment was to estimate the dietary phosphorus requirement (P) for maintenance of kid goats in the growth phase by the endogenous loss method and comparative slaughter technique. Twenty-one males, average 18 kg LW, were used. From those, three were slaughtered at the beginning of the experiment, as reference, and the remaining 18 animals were fed isocaloric and isoproteic diets in a completely randomized design with 3x2 factorial arrangement (level of dietary P [0.12, 0.21 and 0.29% as fed] and feeding way of the diet [restricted and ad libitum]). The experimental period was 37 days, with 30-day of adaptation and seven days for total collection of feces and urine. At the end of the collection period, three animals, from each treatment, were slaughtered. The dietary requirements of P for maintenance were estimated the by fecal and urinary endogenous loss (endogenous loss) and the P retention in the animal body in relation to their intake and in that retained in the reference animal (comparative slaughter). The average values were: coefficient of apparent and real absorption of P, -157±30, 98±10, 43±24, and 65±33; 235±09, 145±24%, respectively; daily fecal and urinary endogenous loss of 8.84 and 4.84 mg kg/ LW, respectively, P balance 187.62±153.87; 14.0±160.59; 85.96±337.85 mg/d; and -11.42±10.98; 1.04±9.14; -2.33±11.69 mg/kg LW, respectively. The daily dietary P requeriments for maintenance were estimated in 72 and 58.46 mg/kg LW by the endogenous loss and comparative slaughter, respectively.