Analysis of systematic and genetic effects on the prevalence of primary cataract, persistent pupillary membrane and distichiasis in the two color variants of English Cocker Spaniels in Germany

Genetic parameters were estimated for prevalences of primary cataract (CAT), persistent pupillary membrane (PPM) and distichiasis (DIST) in 615 single-colored and 617 multi-colored English Cocker Spaniels (ECS) bred in the German kennel club for Spaniels (Jagdspaniel-Klub e.V.). CAT or CAT diagnosed in dogs up to three and a half years of age (early-onset cataract, CAT-early) and CAT diagnosed in dogs over three and a half years of age (late-onset cataract, CAT-late), PPM and DIST were included as binary traits in multivariate genetic analyses. Heritabilities on the underlying liability scale were 0.15 for CAT, 0.34 for CAT-early, 0.13 for CAT-late, 0.46 for PPM, and 0.62 for DIST in single-colored ECS and 0.06 for CAT, 0.13 for CAT-early, 0.14 for CAT-late, 0.10 for PPM, and 0.61 for DIST in multi-colored ECS. There were indications for a different genetic basis of CAT-early and CAT-late in single-colored ECS as genetic correlations were close to zero. In multi-colored ECS, a similar tendency for CAT-early and CAT-late could be observed.