Addition of increasing doses of ricinoleic acid from castor oil (Ricinus communis L.) in diets of Nellore steers in feedlots

The aim of this study was to evaluate the performance and blood parameters of feedlot Nellore cattle fed increasing doses of ricinoleic acid (RA) in the diet. Ninety-six Nellore steers divided into 12 groups of 8 animals were used. The animals were randomly assigned to four treatments: 0, 1, 2, or 4 g of RA/animal/day, with three replicates per treatment. The experimental period consisted of 84 days divided into three 28-day periods preceded by three step-up diets. A quadratic effect was found for average daily gain and final body weight, as well as for leukocyte and lymphocyte counts, and for urea and blood urea nitrogen. A linear effect was observed for albumin, alkaline phosphatase, and gamma glutamyl transferase. The inclusion of 2 g of RA daily improved the performance of feedlot Nellore steers.