Thirty Canchim cows, averaged 471 kg of body weight and 50 months old, were fed with supplement during the dry season of 1998, in order to evaluate the precision of the predicted performance for different systems of diet evaluation. The supplements were composed of corn silage, corn grain, citrus pulp, cottonseed meal, soybean meal and whole soybean, in agreement with the recommendations of the Metabolizable Protein System (MP); Cornell Net Carbohydrate and Protein System (CNCPS); and Intestine Digestible Protein System (PDI), for body weight maintenance. The daily body weight change obtained did not differ among treatments CNCPS, MP and PDI, with 0.34; 0.33; and 0.19 kg/head, respectively. When the meat production was the sole objective, the economic analysis revealed R$22.00; R$-44.73; and R$47.27/ha/year for MP, CNCPS and PDI systems, respectively. It was concluded that the adjusted supplements provided compatible results with the estimated animal performance.
beef cattle; corn silage; cottonseed meal; requirements; soybean meal
