SUMMARY
The present study utilized the pedigree records of 3191 Barki lamb progenies of 186 sires and 1640 dams reared at two research stations; Ras-Elhekma (from 1963 to 1972) and Maryout (from 1973 to 2004). The current study investigated the effect of inbreeding on body weights at birth, BW, weaning, W120, yearling, W360 and at first mating, W480 in Egyptian Barki sheep flock of the Desert Research Centre. The non-genetic factors affecting the studied traits were investigated. It was found that 4.92% of the present dataset were inbred animals. Average inbreeding coefficient of inbred animals was estimated as 3.57% and appeared to be ranged from 0.05% to 25.20%. Estimate of inbreeding regression coefficient on year of birth for inbred animals were significantly negative in Ras-Elhekma (-0.015) and was not significant in Maryout research station (0.003). Results of pooled data from both stations showed that each one percent increase in inbreeding coefficient resulted in a reduction in BW (-0.0156 kg), W120 (-0.0364 kg) and W360 (-0.0079 kg) together with an increase in W480 (0.0559 kg). The effect of inbreeding seemed to be negligible for the studied body weights with no consistent trend in both research stations.