SUMMARY The present study was carried out at the "Departamento de Zootecnia da Universidade Federal de Santa Maria" to evaluate sugar-cane based diets containing different protein sources. The four diets tested were constituted of 75% of dry matter (DM) as sugar-cane and 25% as concentrates formed by: T1 -meat meal + sorghun grain; T2 - rice bran + urea; T3 -soybean meal and T4 - sorghum + urea. All diets had the same level of nitrogen content. Two experiments were conducted with the same diets: in experiment I, 12 castrated male sheep were kept in metabolic cages and used to determine digestibility and intake of the experimental diets during two periods. In experiment II, 16 crossbred 2.5 to 3.0 years old steers with 300kg body weight were distributed, four to each treatment, according to a completely randomized block design and fed in pens for a 84 days period. The results of digestibility and intake obtained were: 59,68; 58,77, 64,69 and 63,53% for dry matter digestibility, 56,32; 51,43; 71,69 and 64,41% for crude protein digestibility, 51,76; 46,99; 53,86 and 62,55% for crude fibre digestibility and 31,30; 34,50; 35,63 and 30,02g/kg PV75 for digestible dry matter intake for treatments T1, T2, T3 and T4 respectively. . Although there was a 0.52kg difference between the highest and lowest average daily gain, this was not statiscally signifficant. Comparing the two diets containing urea (T2 and T4) with those containing mainly true protein (T1 and T3) it was shown that the protein source affect body weight gain in steer, 1.16kg for treatments with urea and 1.51 kg for the other two treatments.
sugar-cane; feedlot; meat meal; soybean meal; rice bran; urea
