Comparison of five crossbreeding types involving Timahdit, D'man and improved terminal sire breeds of sheep: ewe reproduction, lamb survival and growth performance

A crossbreeding experiment involving Timahdit (T), D'man (D) and improved s ire breeds (M) was conducted to compare lamb production in five crossbreedi ng types: D X D, T X T, D X T (DT), M X T, and M X DT lambs. Reproductive a nd production traits were analysed in 1187 litters, 1586 lambs born and 134 6 lambs weaned, progeny of 605 ewes. Effects of crossbreeding type, year of birth, sex of lamb, age of dam, and type of birth were significant on the majority of traits studied. The D X D and M X DT crossbreeding system showe d the highest litter sizes at lambing and at weaning with respective values in D X D (2.17, 2.34) and M X DT (1.72, 2.39). Ewes bearing the M X DT cro ss lambs showed the highest (P < 0.05) litter weight at weaning (28.28 kg) followed by those with M X T (23.14 kg), and D X D (22.53 kg) lambs. M X DT and M X T lambs were heavier and grew faster than the of her lambs. On the of her hand, lamb survival rates and growth traits were the lowest in D XD but those in T X T and D X T genetic types of lamb were intermediate. Resu lts showed that D as a dam breed had a favourable effect on litter size (P< 0.01) but unfavourable effect on lamb survival and birth weight. The reprod uctive performance of DT crossbred ewes, due to their high prolificacy and lamb survival, associated with the favourable effect of an improved termina l sire (M) for growth traits, indicated that the three breed cross (M X DT) could enhance lamb production in Morocco.