ESTIMATES OF GENETIC AND PHENOTYPIC PARAMETERS FOR GROWTH TRAITS OF DMAN LAMBS

The heritability of growth traits from birth to 6 months of age and the genetic and phenotypic correlations among them were determined from paternal half-sib analyses of 1689 records of D'man lambs. Heritability estimates were 0·34 (s.e. 0·08), 0·23 (s.e. 0·06), 0·52 (s.e. 0·10) and 0·43 (s.e. 0·09) for weights at birth, 30 days, 90 days and 180 days, respectively. Heritabilities for average daily gains from birth to 30 days and from 30 to 90 days were estimated to be 0·12 (s.e. 0·05) and 0·56 (s.e. 0·11), respectively. Genetic and phenotypic correlations among growth traits were all positive and of high magnitude. The former estimates varied from 0·66 to 0·98, the latter estimates ranged from 0·23 to 0·92. Selection for high weight at 90 days would be expected to have large effect on other growth traits as a result of their large positive genetic correlations. © 1990, British Society of Animal Science. All rights reserved.