Heritability of Face Covering and Neck Folds in Range Rambouillet Lambs as Evaluated by Scoring

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Abstract
Estimates of heritability of face covering and neck folds, as evaluated by scoring, were calculated from data on 2183 weanling Rambouillet lambs born in 1941 and 1942 and 892 dam-offspring pairs. Two breeding methods had been followed, consisting of inbred lines and top crosses. Estimates based on daughter-dam regressions and half-sib correlations were calculated for each yr. and breeding method. The averages of these 8 estimates indicated that the heritability of face covering was about 56 [plus or minus] 5%, while that of neck folds was 39 [plus or minus] 5%. No significant differences were found between estimates for yrs., breeding methods, or methods of estimation. Significant variations between inbred lines were found for each trait. Both face covering and neck folds were highly heritable when compared with other traits in weanling Rambouillets. Open face should be emphasized in selecting lambs because it has considerable economic importance and because its high heritability indicates that rapid progress toward open face can be made by selection on phenotypic merit at weaning time. By Using ram lambs in breeding, any gain made in one yr. may be taken advantage of immediately through the sire. Where considerable progress has already been made toward elimination of folds, as in the flock studied here, less attention can be given to neck folds in weanling''selections. Emphasis on progeny test information may be necessary for further progress in elimination of folds.
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