Diet Botanical Composition of Goats on Rangeland Treated with Trenbolone Acetate

An experiment was conducted to examine how Trenbolone Acetate (TBA, 33 mg)/estradiol-17β (E2, 5 mg) implant affect diet selection of pluriparous mixed-breed goats (n = 10 per treatment) grazing in a highly degraded microphyll desert scrub of northern Mexico. Diets of goats were examined using microhistological fecal analysis during the peack growth of forages (August-October). TBA-E2 caused a 48% increase (p<0.01) in daily weight gain of goats. Woody plants were the main component of goat diet with no differences between implanted and nonimplanted goats (64±7 vs. 65±8% across months of study). Differences between diets of implanted and nonimplanted goats were mainly an increase (p<0.01) in Acacia farnesiana, Agave lechuguilla and Larrea tridentata. Also, the implanted goats used more (p<0.01) forbs than nonimplanted goats. Results indicated higher proportions of both highly palatable and unpalatable forages in the diet of the TBA-E2 implanted goats compared with control goats which suggests that the administration of these anabolic compounds for an extended period of time modifies food selection of goats in this xeric landscape.