Breeding for health using producer recorded data in Canadian Holsteins

Health traits are of increasing importance to dairy producers. In the Scandinavian countries, direct selection for improved disease resistance has been carried out for more than 30 years (Philipsson and Lindhé, 2003). In these countries, veterinary treatments are recorded, as all treatments involving antibiotics and hormones have to be made primarily by a veterinarian. As veterinarians have extensive knowledge in disease diagnoses, a large number of different health disorders are recorded, e.g. the Norwegian disease code includes 67 different diagnoses (Østerås et al., 2007). Recently a similar disease recording system has been established in Austria (Egger-Danner et al., 2011). In Canada, a national dairy cattle health and disease data management system was started in 2007. In contrast to the Scandinavian approach, recording is done by producers, as producers are allowed to initiate treatments using antibiotics or hormones. Eight specific diseases that are known to affect herd profitability are recorded by producers on a voluntary basis: mastitis, displaced abomasum, ketosis, milk fever, retained placenta, metritis, cystic ovarian disease and lameness. Producers were provided with disease definitions, adapted from work by Kelton et al. (1998), as a guide for identification and recording of the eight disorders. Health data is recorded by producers using on-farm herd management software (e.g. Dairy Comp, Agri-Lacta) or record books. Data are collected by milk recording technicians at each test day herd visit and forwarded to the Canadian Dairy Herd Improvement (DHI) database. Besides, health data from producers participating in the “Dossier Santé Animale/Animal Health Record” (DS@HR) program is collected and forwarded to the DHI database by their veterinarians. In 2010, about 30% of all recorded health events originated from on-farm herd management software, 30% from record books and 40% from the DS@HR program. The objective of this study was to investigate if health data recorded by Canadian dairy producer can be used for genetic evaluations. The specific objectives were to 1) analyze data quality, 2) calculate disease frequencies and, 3) estimate heritabilities and genetic correlations among health disorders.