Abstract :
[en] Routine recording of claw health status at claw trimming of dairy cattle have been established in several countries, providing a valuable database for genetic evaluation. In this review, issues related to genetic evaluation of claw health are examined; data sources, trait definitions, and data validation procedures are discussed; and a review of genetic parameters, possible indicator traits, and status of genetic and genomic evaluations for claw disorders are presented. Different sources of data and traits can be used to describe claw health, including veterinary diagnoses, data from lameness and locomotion scoring, activity-related information from sensors, and foot and leg conformation traits. The most reliable and comprehensive information is probably data from claw trimming. Heritability of the most commonly analyzed claw disorders based on data from routine claw trimming were in general low, with linear (threshold) model estimates ranging from 0.01 to 0.14 (0.06-0.39). Estimated genetic correlations among claw disorders varied from -0.40 to 0.98. The strongest genetic correlations were found among sole hemorrhage (SH), sole ulcer (SU), and white line disease (WL), and between digital/interdigital dermatitis (DD/ID) and heel horn erosion (HHE). Genetic correlations between DD/ID and HHE on the one hand and SH, SU, or WL on the other hand were low in most cases. Although some studies were based on relatively few records and the estimated genetic parameters had large standard errors, results were generally consistent across studies. Routine genetic evaluations of direct claw health have been implemented in The Netherlands (2010), Denmark, Finland and Sweden (joint Nordic evaluation; 2011), and Norway (2014), and other countries plan to implement this in the near future.
