Growth performance of native goats fed diets containing different levels of energy

Castrated male goats (n = 40) of the Moxoto (n = 20) and Caninde (n = 20) breeds with an average weight of 15.3 kg were studied to determine intake, nutrient digestibility and weight gain for two diets with different energy levels. The experiment utilized a 2 x 2 factorial arrangement (two breeds and two diets), in which goats were randomly allocated. A diet of low energy density and a forage: concentrate ratio of 70: 30 was utilized along with a diet of high energy density and a forage: concentrate ratio of 35:64. To determine the nutrient intake and digestibility, at the end of the experiment, goats were kept in metabolism cages for a period of 15 days. Weighing of the goats was conducted weekly over a period of 90 days. The goats that were fed a diet of high energy density displayed significantly increased consumption of metabolic fractions, with the exception of dry matter and neutral detergent fiber, when compared with those fed a diet of low energy density. The lack of difference in dry matter and neutral detergent fiber intake indicated that goats have a high digestive capacity for the diet containing a greater quantity of Manicoba hay. Weight gain was significantly greater for those on the diet of greater energy density. Among the breeds, Caninde goats recorded the highest average consumption and weight gain. Coefficients of digestibility were significantly greater for the more energy dense diet, with no difference between breeds. Regardless of diet, the Caninde breed shows greater weight gain than the Moxoto breed.