Inbreeding effects on body weight traits of Iranian Moghani sheep

Abstract. The objective of the present study was to evaluate the effects of inbreeding on body weight at different ages in Moghani sheep. Traits included were birth weight (BW), 3-month weight (3MW), 6-month weight (6MW), 9-month weight (9MW), and yearling weight (YW). Data and pedigree information used in this study were collected at the Breeding Station of Moghani sheep, Iran during 1987-2005. All the animals were grouped into three classes according to the inbreeding coefficients obtained by their pedigree: the first class included non-inbred animals (F=0 %); and the second and third classes included inbred animals (00.10, respectively). Average inbreeding rate was 2.93 % in the pedigree of Moghani sheep. The BW of animals within second class of inbreeding was significantly higher than those of lambs belonging to the third class (P<0.05). The 3MW of animals within third class of inbreeding was significantly (P<0.05) higher than those of lambs belonging to the first and second classes. The 6MW of animals within third class of inbreeding was significantly (P<0.05) lower than those of lambs belonging to the first and second classes. Animals within third class of inbreeding had greater mean of 9MW than two other groups (P<0.05). Also, the YW of animals within second class of inbreeding was significantly (P<0.05) lower than those of lambs belonging to the first and third classes. The utilization of designed mating system could be a suitable approach to maintain the level of inbreeding under control.