AN INVESTIGATION INTO GENETIC EVALUATION USING AN ANIMAL-MODEL WHEN PATERNITY IS UNCERTAIN

A study was conducted to examine the effect of using Henderson's (1988 ) 'average numerator relationship matrix' (ANRM) on the prediction err or variance (PEV) of breeding values obtained using an animal model wi th maternal effects. Genetic trends with and without using ANRM were a lso estimated and compared. The results suggest that, in situations wh ere multiple-sire joining is practised, the use of ANRM in mixed model equations will result in lower PEVs than when an ordinary numerator r elationship matrix, treating sires as unknown, is used. Very little bi as in genetic trend estimates was observed when ANRM was used.