Heritability of Type and Condition in Range Rambouillet Lambs as Evaluated by Scoring

Abstract

Estimates of the heritability of type (mutton conformation) and condition (degree of fatness) were made from the half-sib correlations and intra-sire regressions of offspring on dam from data on 2183 range lambs and 892 dam-offspring pairs. The average of 8 estimates indicated that the heritability of type was about 13 ± 4 percent, while that for condition was about 4 ± 3 percent. The best methods of selecting and breeding for traits with such low heritability are discussed. Because other traits are more highly heritable and more important for total production in sheep, it seems that type and condition should receive relatively less emphasis, than is given in present practice, in a sound breeding program directed toward the improvement of sheep.