This work was carried out in order to evaluate the daily weight gain of two sheep genotypes, Santa Inês and F1 Dorper x Santa Inês. Eight females and eight males from each genotype, were used, in a entirely randomized design, in a factorial scheme 2 x 2 x 2 (two genotypes, two sexes and two slaughter ages). Data were submitted to analysis of variance with application of the Scott-Knott test at 5% probability. The birth weight, wean weight, final weight, average daily weight gain and total weight gain were evaluated. There was significant effect of genotype for birth weight and wean weight with superior Dorper x Santa Inês lambs. There was no significant difference for final weight, since weight gain from wean to slaughter was superior for Santa Inês genotype. For total weight gain, the effect of the genotype was important because F1 Dorper x Santa Inês was superior to, while daily weight gain was equal for the two evaluated genotypes. Sex effect was not significant for any evaluated characteristic. There was no difference between final weight, average daily weight gain and total weight gain for different slaughter ages. The use of Dorper breed did not reflect greater return when is intended to keep its products in systems exclusively for pasture. Bioeconomic studies are necessary for verifying applicability of that practice in the North of Minas Gerais.
crossbreeding; heterosis; sheep; weight gain