Feeding behavior of lambs fed castor meal

Abstract

The experiment aimed to evaluate the feeding behavior of Santa Inês lambs fed diets containing different levels of detoxified castor meal in the concentrate. Twenty-four sheep with an average body weight of 18.5± 2.26 kg, at four months of age, were distributed in a randomized complete design with four treatment and six replications. Treatments consisted of four levels of castor meal (0, 33, 67, and 100%) replacing soybean meal. Animals underwent a 15-day adaptation period and an experimental period of 84 days. The diet was composed of 60% sugarcane silage and 40% concentrate, on a dry matter basis. Animal behavior (idle, rumination, and feeding activities) were observed visually for two 24-h periods with 5-min intervals, and recorded. The number of rumination chews and the time taken to ruminate each cud per day were counted using a digital stopwatch. Dry matter (DM) intake was not affected by inclusion of castor meal in the concentrate, averaging 884.02 g day?1. The feeding activity was not affected by addition of castor meal. Rumination time increased linearly, whereas the idle and rumination times decreased linearly with addition of castor meal. Feeding time, expressed in min per kg of DM and NDF, was not influenced by the inclusion of the meal in the diet, averaging 373.3 and 880.0 min, respectively. The number of chews and the time taken to ruminate each cud were not changed by inclusion of castor meal in the diet. Feed efficiency, expressed in grams DM and NDF per hour, was not influenced by castor meal inclusion in the diet. Rumination efficiency expressed in g DM h?1 decreased, but was not affected when expressed in g NDF h?1. Total replacement of soybean meal by castor meal in the concentrate does not affect the feeding time or feed efficiency of feedlot sheep, but leads to a small reduction of their rumination efficiency. Thus, we recommend the inclusion of castor meal in sheep diets at the levels tested in this study.