Growth Performance of Rahmani and F1 Cross (Chios x Rahmani) Lambs under the Environmental Conditions of Upper Egypt

This study was carried out in Animal Production Department Farm, Faculty of Agriculture, Al–Azhar University during three consecutive production years (2002, 2003 and 2004). This study aimed to evaluate some productive and reproductive traits in Rahmani sheep and F1 cross with Chios rams (½ C ½ R). A total of 200 Rahmani ewes were bred, and produced 144 lambs (However, 140 lambs born alive and 4 lambs died after birth) of which 116 were raised to weaning. The effect of genetic groups, sex of lambs, year of lambing and season of lambing on birth weight of lambs were not significant, while, type of birth and age of dam had a significant (P < 0.01 or P < 0.05) effects on birth weight of lambs. The crossbred lambs (½ C ½ R) were heavier at birth than purebred Rahmani lambs; Male lambs were heavier than female ones in their birth weight. Also, single born lambs were heavier than twin lambs in their birth weight, and lambs born in summer were, on the average 0.13 kg, heavier than those born in winter at birth. Lambs born by ewes of 4 years–old or more had the heaviest birth weight. Genetic groups had a highly significant (P < 0.01) effect on weaning weight and pre-weaning daily gain of lambs, while, sex of lambs, type of birth, year of lambing, season of lambing and age of dam had no significant effect on weaning weight of lambs. Genetic groups, sex of lambs, type of birth, year of lambing, season of lambing and age of dam had no significant effect on body weight at 6, 9 and 12 months of age or on daily gain at all periods studied .However, the F1 crossbred (½ C ½ R) expressed heavier weights than purebred Rahmani at all periods studied, male lambs were heavier than females, and single born lambs were heavier than lambs born as twins in all body weights studied. Also lambs born in summer was heavier than that of winter ones.