Predictive ability of genomic breeding values for corkscrew claw in Norwegian Red

The aim was to predict genomic breeding values (GEBV) for corkscrew claw (CSC) in Norwegian Red and to investigate whether including historical data from a correlated trait improved the predictive ability of GEBV. Corkscrew claw, the most prevalent claw disorder in Norway, has since 2004 been recorded by claw trimmers. Hoof quality (HQ), a feet and leg conformation trait recorded by breeding advisors, is a highly correlated trait to CSC. A total of 2,114 sires were included in the analyses, of which 1,074 had daughters with CSC records. A 10-fold cross-validation was used to assess predictive ability of GEBV for CSC, using daughter yield deviation as response variable. The mean predictive correlation of GEBV for CSC was 0.29 in univariate analysis, and when including HQ as a correlated trait the predictive ability increased slightly to 0.32.