Browsing by Author "Back, Susanna"

The purpose of this study was to estimate prevalence and genetic parameters of osteochondrosis in the Finnhorse population. Osteochondrosis is characterized by a failure of normal endochondral ossification. This developmental orthopedic disease is widely recognized in young warmblood horses across many breeds. The data consisted of 654 young Finnhorses (Group 1), presented for radiographic examination in the years 2014 – 2015. The total data (n=1829) included also most of the recently used breeding stallions with a high number of progeny. Because of the low frequency of the disease, a low number of analysed horses and challenging pedigree structure with highly variable family size, there were problems in genetic analyses. Heritabilities (h2) were estimated using linear sire model for categorical data and the results were augmented by using non-linear animal model on the liability scale. Statistical analysis was made by R program MCMCglmm which gives posterior distribution (incl. 95 % credibility area). The heritabilities were analysed by joint –specific analyses. The presence of at least one osteochondral lesion was documented for 16,9 % of the studied horses. The lesions were most common in hock (5,2 %) where h2 with linear sire model was 0,18 (95 % credibility area 0,03-0,35). By using linear sire model in Group 1 h2 estimates were in hoof joint of front legs 0,31 (0,12 - 0,55), stifle joint 0,31 (0,09 - 0,54) and dorsodistal osteochondral fragments in fetlock which are originating from metacarbal bone 0,22 (0,07 - 0,40). The prevalence of osteochondrosis is more common in Finnhorse population than has been expected. In future we should focus on the affected joints with the highest frequency and heritability rather than the entire disease complex. The observed genetic variation allows the use of breeding selection for the systematic reduction of osteochondrosis in the Finnhorse population.