Phosphorus requirement of Nelore steers

The nutritional phosphorus (P) requirement of cattle has to consider the mi nimum endogenous fecal loss of this element. In general, ration formulation is based on foreign tables, without taking Brazilian conditions in conside ration. The aim of this study was to determine the endogenous losses of P a nd to estimate the minimum P requirement of Nelore cattle. Eighteen castrat ed steers aged 12 months and weighing 190.82+/-27.53 kg were housed in meta bolism cages. In a 30 day experimental period the animals were fed with hay and a concentrate mixture. Different levels of dicalcium phosphate were ad ded to basal diet as to obtain 0.12, 0.24 and 0.36% of P, based on the tota l dry matter intake. P-32 was intravenously injected and endogenous P losse s were determined. The minimum endogenous fecal loss for zero P intake calc ulated by interpolation was 5.72 mg/kg (LW) per day, and for zero balance, the minimum P requirement was 8.84 mg/kg (LW) per day.