Repeatability and heritability of components of reproductive efficiency in fine-wool sheep.

I MPROVEMENT in reproductive efficiency is one of the important goals with most species of farm or ranch livestock. This is especially true with sheep which seem to offer a great potential in this respect. The part that inheritance plays in reproduction of this species is not well understood. Earlier attempts to determine heritability of this character (Rendel, 1956; Young, Turner and Dolling, 1963; Purser, 1965; Singh and Rempel, 1967) have generally yielded estimates of low magnitude. However, in general, these workers have not considered the components of the composite character, reproductive efficiency of ewes, as separate entities. The purpose of the present study was to investigate the repeatability and heritability of these components in two flocks of Rambouillet sheep.