Desempenho de cordeiros confinados e em pastejo submetidos a diferentes tipos de suplementação.

Abstract

The objective of the present study was to evaluate the effect of different food supplements in the diet of Santa Inês hair lambs, under confinement or rangeland conditions. In the first experiment, six replications of the four treatments were randomly assigned to twenty-four non-emasculated males, with an initial mean body weight of 16.8 kg. These animals were observed during 66 days, including the 21-day adaptation period. The diets were composed of a concentrated mixture (corn and soy bran), and Andrequicé (Leersia hexandra S.W.) and Brachiaria Tanner Grass (Brachiaria radicans Napper) hay. Supplement consisted of a mineral mixture (MM) (123.8 g of Ca/kg, 68 g of P/kg, 12 g of S/kg, 600 ppm of Cu, 100 ppm of Co, 368 ppm of Fe, 120 ppm of I and 12 ppm of Se, 600 ppm of Mn and 600 ppm of Zn). Treatments consisted of 200g of the concentrate-hay diet/day, without (T1) or with (T2) MM, as well as 300g of the concentrate-hay diet/day, supplemented by the complete MM (T3) or by Mn-free MM (T4). Data analyses showed no treatment effect on dry matter intake. However, animals fed T3 and T4 diets presented a higher crude protein intake, that in turn improved mean body weight gain. In the second experiment, six replications of the four treatments (T1, T2, T3 and T4 with the same concentrate and MM composition described for the first experiment, while roughage fodder was provided by field foraging) were randomly assigned to twenty-four non-emasculated males, with an initial mean body weight of 19.9 kg. These animals were observed during 71 days, including the 11-day adaptation period. The animals fed diets T3 or T4 performed better than the T1 and T2 ones, probably due to the enhanced effect of the MM caused by the higher quality of native fresh forage.