Genomic Evaluation for Foot and Claw Disorders in Czech Holstein

Abstract

Genomic breeding values (GEBV) for resistance to foot and claw disorders (CD) have been estimated using a multi-trait model comprising linear type traits and single-step GBLUP. Infectious digital disorders (IDD) included dermatitis digitalis and interdigitalis, interdigital phlegmon, and heel horn erosion; claw horn lesions (CHL) included ulcers, white line disease, horn fissure, and double sole; overall claw disorders (OCD) comprised all the recorded CD. Datasets for IDD, CHL and OCD included 40,859; 25,143; 57,567 Holstein cows and 71,219; 44,265; 100,903 lactations with a lactation incidence rate of 13.3%; 12.5%; 17.0%, respectively. Cows calved between 2017 and 2021 in 46 (IDD), 30 (CHL), and 64 (OCD) herds, respectively. CD traits were binary with 0 (no CD) and 1 (at least one CD) during lactation. Linear type traits were foot angle (IDD, CHL), rear leg set (side view) (CHL), feet & legs score (CHL, OCD), and locomotion (IDD, CHL, OCD). Linear model equations included the random additive genetic effect of animal, and for CD traits, fixed effects of parity and age at calving class, herd-year-season of calving and random effect of the permanent environmental effect of a cow; for linear type traits included fixed effects of herd-year-season of scoring, classifier and linear and quadratic regression on the age at calving and the days of scoring. Pedigree involved 102,862, 72,921, and 130,354 animals. Number of genotyped animals was 12,959; effective SNP 36,520; effective animals 12,672. Variance and covariances in the multi-trait model prediction yielded heritabilities 0.09 foot angle, 0.12 rear leg set (side view), 0.09 feet & legs score, 0.11 locomotion, 0.07 IDD, 0.08 CHL, 0.04 OCD; genetic correlations between IDD and foot angle 0.23, locomotion -0.30, between CHL and foot angle -0.33, locomotion -0.22, rear leg set (side view) 0.21, feet & legs score -0.28, between CHL and locomotion -0.42, feet & legs score -0.27. For young genomic bulls (n=186), average reliability of GEBV: for IDD 0.24 (0.14 to 0.34); for CHL 0.20 (0.10 to 0.27); for OCD 0.26 (0.15 to 0.35).