Preliminary genetic analyses of voluntarily supplied disease data in Australian dairy herds

Abstract

Health disorders data collected from Australian dairy herds were analysed to estimate incidence levels and genetic parameters for some diseases traits and to examine the consequence of selection for Australian profit ranking (the economic index in Australia) and other economic traits on incidence of some diseases. Data on disease problems including udder, leg, reproductive and ‘all disorders’ were extracted from the Australian Dairy Herd Improvement Scheme database for cows that calved in 2007 and 2008 and were analysed fitting a linear sire model. The occurrence of disease problems was as high as 0.3 if ‘all disorders’ were put into one group. Five percent of the cows that calved showed leg problems and the incidence of udder problems was ~0.13. The heritability of all disease problems ranged from 0.01 for reproductive problems to 0.03 for udder problems. The results showed that selection on milk yield traits will likely increase the frequency of all health disorders. Although selection on udder depth and somatic cell count helps to mitigate the possible genetic deterioration in udder problems, it is unlikely to avoid it totally. Therefore, more effort to collect and analyse health event data from Australia dairy herds could help to better design genetic and environmental measures to reduce the consequence of health problems.