DIRECT AND MATERNAL VARIANCE COMPONENT ESTIMATES FOR CLEAN FLEECE WEIGHT, BODY-WEIGHT AND MEAN FIBER DIAMETER IN THE GROOTFONTEIN MERINO STUD

Direct and maternal variance components and resulting heritabilities w ere estimated by DFREML-procedures for clean fleece weight (CFW), body weight (BW) and mean fibre diameter (MFD) in the Grootfontein Merino stud. Direct heritabilities were estimated as 0.381, 0.289 and 0.626 f or BW, CFW and MFD, respectively. The maternal additive variance estim ates were low, resulting in heritability estimates of 0.013 for BW, 0. 027 for CFW and 0.012 for MFD. The estimated covariances between direc t additive and maternal additive effects (sigma(am)) were positive for BW and negative for CFW and MFD. The proportion of sigma(am) to the p henotypic variance was 4.0%,-3.1% and -2.4% for BW, CFW and MFD, respe ctively. It is concluded that the maternal component can be ignored du e to its relative small effect on these traits.