This study was conducted to investigate the preweaning growth of Turkish Merino (M) purebred and Lincoln (L) x (LxM), German Blackheaded Mutton (GBM) x (GBMx M). Hampshire Down (H) x (HxM), GBM x (GBM X Akkaraman (A)), H x (H x A), GBM x (GBM x Awassi (I)) and H x (H X I) Bl crossbred lambs. The data were obtained from 19, 22.23. 14. 10, 11, 9 and 12 lambs for each genotype, respectively. The lambs were fed alfalfa hay, concentrated ad libitum and suckled and then weaned at 100 days of ages.

In this study, the birth weight averaged 4.5, 4.4, 4.7, 4.9. 4.2, 4.9, 4.9 and 4.6 kg for genotypes, respectively; weaning weight 23.8, 24.8, 27.5, 26.2, 24.8, 27.4, 26.6, and 26.7 kg and growth rate 201.9, 212.7, 244.3. 225.6, 196.5, 235.6, 224.9 and 230.1 g/day. For three characters, the differences between genotypes were not significant.

The effect of age of dam on growth rate was significant (P<0.05) but on birth and weaning weight was not. The effect of sex of lambs on this three characters was not significant. The birth type (single/twin) has significantly affected the birth weight (P<0.01) but the weaning weight and growth rate has not. The birth weight and sucked milk have no signfhant source of variance on growth rate.