Comparison of three terminal sire breeds for meat crossbred lambs in Morocco

Crossbreeding between 602 Timahdit (T) and F1 (D'man x Timahdit) as dam lin es acid lie-de France (IF), Lacaune (L), and Merinos precoce (MP) as sires lines were evaluated for ewe reproductive performances and production perfo rmances on 860 lambs and 150 slaughtered lambs. Ewes mated to IF showed the lower fertility rate (-7%) than those mated to L and MP. However, for litt er size and weights the difference were not significant, Genetic group of e wes had highly significant effects on these traits, At 90 days of age after lambing, the F1 ewes weaned +0.47 more lambs and produced 6.69 kg more tha n T ewes. However, finished lamb growth rates of L and MP were lower than t hose of IF. The later lambs realized also the best conversion index of feed , weight carcass gains, dressing percentage, and larger Longissimus muscle area than lambs sired by L and MP. Lambs sired by L had trend to deposit mo re mesenteric fat and longer carcasses. Dam genetic group did not show diff erences for the majority of carcass traits. It was concluded that IF rams a s terminal sire seems more suitable for lambs production under intensive pr oduction system, where L should be more suitable under less intensive lambs production systems. Furthermore, with regard to the overall productivity t he Fl dams will be a genetic group of choice to improve meat production in Morocco.