Aim: In this study, we investigated the effects of gender and birth type of lambs on birth weight, weaning weight and daily live weight gain using meta-analysis.

Materials and Methods: The selected 51 research results according to specified criteria and obtained from published articles between 1990 and 2011. Consistent estimates of the effect size of the each research based on averages with meta-analysis have been calculated. Because the heterogeneity between studies for the factors effecting the growth characteristics was found significant (P<0.05), random effects model was used in meta-analysis. Because of insufficient and unsuitable data, dam age factor has not been evaluated.

Results: The effect size of gender was found as 0,39 for birth weight, 0,47 for weaning weight and 0,62 for daily live weight gain and all of them were found significant (P<0.001). According to this, the effect of gender on birth weight, weaning weight and daily live weight gain was to be significant. The effect size of birth type was found as 1,14 for birth weight, 0,76 for weaning weight and 0,47 for daily live weight gain and all of them were found significant (P<0.001).

Conclusion: According to meta-analysis made in this study, the gender and birth type factors were found effective on birth weight, weaning weight and daily live weight gain of lambs.