ABSTRACT
A total of 3151 birth weight (BW) and weaning weights (WW) of Egyptian Farafra lambs was used to investigate the possibility of incorporating these traits in a selection program. Data was collected during the period 1995-2009 for animals raised in Mallawi Animal Production Research Station, (latitude 28º 07 and longitude 30º 33 E), of the Animal Production Research Institute (APRI). Al-Menya Governorate, north of Upper Egypt.
Fixed effects were year of birth, season of birth, age of dam at lambing, type of birth and sex of the Lamb. The heritability (h2), additive maternal effect (m2), genetic (rg) and phenotypic (rp) correlations and permanent environmental effect (c2) were estimated using the Multiple Trait Derivative Free Restricted Maximum Likelihood program (MTDFREML) (Boldman et al. (1995)). The results showed that all the fixed effects contributed significantly (P<0.01) to the variation of the studied traits. Direct genetic heritability of BW and WW were 0.25±0.02 and 0.21±0.03, respectively. The corresponding additive maternal effect (m2) estimates were 0.40±0.01 and 0.19±0.01, respectively. Phenotypic and genetic correlations between BW and WW were 0.52±0.01 and 0.37±0.03, respectively. Maternal genetic correlation estimate between BW and WW was 0.16± 0.05 while, the estimate of permanent environmental effect (c2) for BW and WW, as a proportion of total phenotypic variance, was 0.38±0.02 and 0.20±0.04, respectively. Improvement of birth and weaning weights of Farafra sheep seems feasible with selection programs, as some of the related traits are moderately heritable and those traits specially are well correlated, which could suggest that these traits are useful in selection programs.