EXAMINING POSSIBILITY OF APPLYING HOMOZYGOSITY INSTEAD OF INBREEDING COEFFICIENT IN CONTROLLING INBREEDING DEPRESSION

Increasing rate of inbreeding coefficient will have harmful effect on important traits such as traits with low heritability such as longevity and the calving interval and age at first calving (Mc Parland et al., 2007). Today it is practically impossible in a given dairy cattle breed to find animals without multiple genetic ties to certain individuals (Croquet et al., 2006). The rate of individual homozygosity ,regardless of having common ancestor or not, causes the same depression in locus with over-dominance effect while coefficient of inbreeding is only an estimation of homozygosity rate using pedigree and therefore is inefficient for incomplete pedigree. Objective of this study is comparison of two methods in controlling unfavorable genotype. Common method is control of unfavorable genotype considering parents relationship. This method is with probability so it is possible on individual high fitness is deleted despite progeny have not unfavorable genotype. Until possibility of detecting individual genotype is impossible this method was only possible method but the second method will be used to detect parents genotype instead of coefficients of inbreeding to consider possible progeny genotype and to determine index for unfavorable genotype

Keywords:

Genomic selection , Homozygosity , Inbreeding depression