Inbreeding Effects on Average Daily Gains and Kleiber Ratios in Iranian Moghani Sheep

Abstract

The objective of the present study was to evaluate the effects of inbreeding on average daily gains and Kleiber ratios in Moghani sheep. Traits included average daily gain from birth to 3 months (ADG1), average daily gain from birth to 6 months (ADG2), average daily gain from 3 months to 6 months (ADG3), average daily gain from 3 months to 9 months (ADG4), average daily gain from 3 months to yearling (ADG5) and corresponding Kleiber ratios (KR1, KR2, KR3, KR4 and KR5, respectively). Data and pedigree information used in this study were collected at the Breeding Station of Moghani sheep 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). There were significant regression coefficients of ADG5 and KR5 on inbreeding of all lambs for changing 1% inbreeding (P<0.01). Indeed, there were significant regression coefficients of ADG3 (P<0.01) and KR3 (P<0.05) on inbreeding of twin-born lambs for a change of 1% in inbreeding. In addition, there were significant regression coefficients of ADG1 (P<0.05) and ADG5 (P<0.05) on inbreeding of male lambs and significant regression coefficient of ADG2 (P<0.05) on inbreeding of female lambs for a change of 1% in inbreeding. Effects of inbreeding on average daily gains and Kleiber ratios in Moghani sheep was not very pronounced in the flock. Planned matings are, however, suggested to avoid accumulation of inbreeding and appearance of its deleterious effects.