Genetic Parameters of Objectionable Fibres, Skin Spots and Halo-hair in Corriedale Sheep

Abstract Text: This study aimed to determine genetic variation and relationships among the binary traits presence/absence of objectionable fibres (pigmented (PPF), medullated (PMED) and kemps (PK)), dark skin spots (PS), and halo-hair on the birth coat (PH). Data from two experimental Corriedale flocks were used, including records from 1421, 656 and 774 animals for PS, fibres and PH, respectively. Bivariate and multivariate models under a Bayesian approach were used for the analyses. Heritability estimates were low to intermediate (0.22 - 0.57). Due to the small amount of data, most genetic correlations presented great uncertainty, thus not allowing establishing clear genetic associations. PPF did not appear to be strongly correlated with PH, but showed a positive and intermediate correlation with PS; therefore PS could be a good indicator for PPF, since it can be easily and quickly assessed on the field.

Keywords: Genetic correlations, Halo-hair, Spots