Evaluation of Levels of fat protected and concentrate on productive performance and sheep thermoregulation

Abstract

The objective was to verify the effect of energy supplementation by including protected fat and increasing the concentrate fraction of the diet on the performance and thermoregulation of confined Santa Inês sheep in the semiarid region of Paraíba. Thirty non-castrated Santa Ines male lambs were randomized in a 3 x 2 factorial (3 concentrate levels: 40, 50 and 60%, and 2 levels of protected fat: 0 and 2%) arrangement according to a complete randomized block design with 5 replications. We observed a positive linear effect of the concentrate levels on animal performance. Energy supplementation with protected fat (2%) did not affect animal performance (P > 0.05), however, there was a significant level of concentrate x protected fat interaction on rectal temperature and respiratory rate. The 60% concentrate level in the diet of confined lambs promoted better performance. The level of concentrate in the diet directly affected the physiological responses of lambs, however the use of 2% of protected fat in the diet when associated with the 40% concentrate level mitigated the effects of heat stress on these animals.