The objective ofthis work was to evaluate the effect of multiple supplement with different levelsof castor meal (Ricinus communis L.) treated with calcium oxide on intake,on the total apparent digestibility of dietary components, on the efficiencyof microbial synthesis and on the performance of beef heifers grazing Brachiariadecumbens during the dry-rainy transition period. The experimental areawas composed of five 2.5-ha paddocks with availability of potentially digestibledry matter of 2,858.4 kg/ha. It was used 25 Nellore heifers and 10 crossbredwith predominance of Zebu breed heifers at 13 months of age and body weightof 210 ± 0.8 kg in a completely randomized experimental design. Supplementscontained approximately 25% of crude protein (CP) and they were formulated with0; 33; 67 and 100% of castor meal replacing soybean meal. Daily weight gainwas 366.1 g for animals in the control group and 439.7; 478.9; 556.3; and 493.9,respectively for those fed supplements with 100% of soybean meal and 33, 67and 100% castor meal. There was no effect of treated castor meal levels on dailyweight gain of the animals, which was higher in those animals fed supplements.Levels of castor meal had decreasing linear effect on intakes of dry matter(DM), organic matter (OM), ether extract (EE), digested dry matter and digestibleneutral detergent fiver and on the intake of total digestible nutrients. Coefficientsof apparent digestibility of DM, OM, CP, EE and non-fibrous carbohydrates weregreater for animals under supplementation. Microbial efficiency, expressed ing of crude protein per kg of consumed TDN, did not differ among groups. Replacementof soybean meal by castor meal treated with calcium oxide does not harm animalperformance.
