RELATIONSHIPS BETWEEN EARLY GROWTH TRAITS IN THE ELSENBURG DORMER SHEEP STUD

Correlations were estimated from a total of 7 740 lamb records, collec ted from 1943 to 1990, from the progeny of 215 sires of the registered Elsenburg Dormer sheep stud. Phenotypic correlations were generally p ositive and medium to high except for a very small negative correlatio n (-0.06) between birth weight (BW) and Kleiber ratio (KL) (ADG/WW0.75 ). A moderate negative genetic correlation (-0.279) between BW and KL was obtained. The estimated genetic correlations between weaning weigh t (WW), average daily gain (ADG), and KL were close to unity and had s mall standard errors. Correlated responses in WW and ADG associated wi th a 10% increase in KL were 20.4% and 24.6%, respectively. Birth weig ht is also expected to decrease by 7.5% with an increase of 10% in KL. A curvilinear model was fitted to represent the relationship between WW and KL. The results suggest that animals should initially be culled on low WW and finally selected on important post-weaning traits.