Utilization of castor bean meal treated with calcium hydroxide, fed wet or dry, by lambs

• Soybean meal was replaced by detoxified castor bean meal in finishing lambs diets.
• Treated castor bean meal was fed either wet or dry at 50 or 100% substitution.
• The soybean meal can be totally replaced by treated castor bean meal without losses.
• Castor bean meal can be fed wet, 18 h after the start of detoxification.

Effects of replacement of soybean meal by wet or dry castor bean meal (CM) in diets of feedlot lambs on animal performance, carcass traits, intake, digestibility and hepatic function were assessed. Thirty-five mixed-breed woolless lambs averaging 20±0.26 kg body weight were randomly assigned into five treatments in a 2×2+1 factorial design with 7 animals per treatment. Control animals were fed a diet containing soybean meal while lambs from the remaining groups received diets with 50 or 100% level by dry (DCM) or wet (WCM) calcium hydroxide treated CM as a replacement of soybean meal. Lambs were fed for 70 days and slaughtered at the end of the trial for further carcass traits evaluation. Dry matter intake and digestibility, final body weight, average daily gain and carcass weights were not affected (P>0.05) by the substitution of soybean meal by either CM source. Serum levels of aspartate aminotransferase and alanine aminotransferase enzymes did not differ among treatments (P>0.05) indicating no effect of treated CM on hepatic function. These results suggest that castor bean meal treated with calcium hydroxide solution (60 g/kg) can totally replace the soybean meal (up to 18% of dry matter of diet) in the diet of finishing lambs without negative effects on weight gain, intake, digestibility and hepatic function. Castor bean meal treated with calcium hydroxide solution can be fed to animals after 18 h in room temperature, in wet form, without sun or oven-drying.