A retrospective analysis of canine hip dysplasia in Hovawart population in the Czech Republic.

The aim of this study was to evaluate the occurrence of individual types of canine hip dysplasia during 25 years of breeding the Hovawart breed in the Czech Republic and to determine the effect of negative selection on the subsequent occurrence of canine hip dysplasia in the following generations of animals. During the study period, from 1998 to 2022, a total of 3,297 radiographs of Hovawart dogs were analysed. The study period was divided into 5 groups (1998-2002; 2003-2007; 2008-2012; 2013-2017 and 2018-2022) and the dogs were divided into three groups according to the severity of hip dysplasia (CHD-A, CHD-B and CHD-C/E). The results show that there was a statistically significant decrease in the incidence of the more severe form of dysplasia during the study years, from 20.54% in 1998-2002 to 1.91% in 2018-2022. In the last period studied, 2018-2022, the proportion of CHD-A in the Hovawart population that underwent radiographic examinations was 92.99%. It can also be noted that younger dogs (up to 2 years of age) had a lower percentage of incidence of the more severe form of dysplasia (7.32%) compared to dogs over 3 years of age (12.04%). This may be influenced by progressive degenerative changes in the joints that develop with age. The yeartoyear decrease in the incidence of dysplasia may indicate a positive effect of stricter selection of dogs entering the breeding programme in the Czech Republic.