Genetic parameters for foot and claw disorders in Czech Holstein cattle

Our study investigated the genetic variability of specific foot and claw disorders, namely dermatitis digitalis, sole ulcer, and three broader categories (infectious diseases, claw horn lesions, and general claw disorder) in Czech Holstein cows. We also examined their genetic relationships with clinical mastitis and key fertility traits. Using both linear and threshold animal models, we concluded that heritability estimates for foot and claw disorders were consistently higher when employing the threshold model. A significant finding was the genetic correlation between sole ulcer and dermatitis digitalis, which ranged from 0.21 (calving to 305 days in milk) to 0.53 (calving to 90 days in milk). Furthermore, we observed stronger genetic correlations between clinical mastitis and overall foot and claw disorders, claw horn lesions, and infectious diseases during early lactation (calving to 90 days in milk) compared to the entire lactation period. Within this early lactation phase, the strongest genetic correlation was identified between clinical mastitis and claw horn lesions. Interestingly, our research uncovered a unique genetic link between days open and dermatitis digitalis, suggesting that a genetic predisposition to a higher occurrence of dermatitis digitalis may coincide with shorter days open. These results underscore the importance of implementing distinct genetic selection strategies for infectious claw diseases and claw horn lesions in dairy cows. This distinction is crucial due to their differing genetic correlations with other economically important traits, ultimately contributing to a better understanding of claw health genetics and its application in breeding programs.