Sire predicted transmitting ability for conformation and yield traits and previous lactation incidence of foot lesions as risk factors for the incidence of foot lesions in Holstein cows

The aims of the present study were (1) to investigate the repeatability of foot lesions [sole ulcers (SU), white line disease (WLD), and digital dermatitis (DD)] across multiple lactations, (2) to evaluate the effect of foot lesions on cow survivability and milk production across multiple lactations, and (3) to investigate the role of sire predicted transmitting ability (PTA) for conformation and production traits as risk factors for the incidence of SU, WLD, and DD. Data were collected from a dairy farm located in Cayuga County, New York. A total of 11,442 cows having first calved during the period from May 13, 2001, to March 26, 2012, were enrolled in the study. Data regarding sire genetic evaluations were obtained from DairyBulls.com (http://www.DairyBulls.com). Lameness was detected and treated and lesions were recorded into a dairy record database (DairyCOMP 305; Valley Agricultural Software, Tulare, CA) by trained farm employees. All demographic, production, and foot lesion data were extracted from DairyCOMP 305 and merged with the sires' PTA information to form a unique database. Mixed logistic regression, general linear mixed, and multivariable Cox proportional hazards models were used to analyze the data. Sole ulcers, WLD, and DD incidence was significantly higher for cows affected with SU, WLD, or DD in previous lactations. Cows affected with WLD or DD during the first lactation had significantly higher WLD or DD incidence during the second and the third lactations. Cows affected with SU or WLD during their first lactation had significantly lower milk production during the second lactation and cows diagnosed with SU, WLD, or DD during their second lactation had higher second-lactation mature-equivalent 305-d milk yield. Sire PTA for milk and protein yield were significantly associated with the incidence of SU, WLD, and DD and incidence of SU and WLD, respectively. Sire PTA for several conformation traits were found to be associated with SU, WLD, and DD incidence. Cows that were affected with SU or WLD during their first lactation were at 1.18 or 1.43 higher hazard of culling than unaffected cows, respectively. In summary, we conclude that SU, WLD, and DD are highly repeatable across lactations and that high genetic merit for milk and protein production as well as milk production (phenotype) were significantly associated with higher risk of SU, WLD, and DD. Additionally, sire PTA for several conformation traits were significantly associated with their daughters' foot lesion incidence.