Genotype of Holstein-Friesian on Grass-Based Systems Affects the Severity of Hoof Disorders

The severity of hoof disorders (HD) was assessed in 3 genotypes of spring calving Holstein-Friesian (HF) cows differing in overall genetic potential as expressed in the Irish ‘economic breeding index’ (EBI). Cows (n=126) were randomly allocated to one of two grass-based feed systems (FS). Assessments of hind feet at 35 and 230 days in milk (DIM) were analysed separately. HD were scored as ordinal (0= absent to 4= severe; i.e. digital dermatitis, sole haemorrhages, white line disease and heel erosion) and binary traits (0 absent, 1= present; i.e. sole ulcer, abscess, under run soles). The ordinal traits were analysed as binary variables using different thresholds. The effect of genotype on HD did not differ with FS except for digital dermatitis (Table 1).
The effect of genotype varied depending on the threshold chosen for the ordinal traits. Higher EBI cows had lower incidence of digital dermatitis (Figure 1) and white line disease (Figure 2) at 35 DIM and 230 DIM, respectively compared to lower EBI cows ...