Radiographic findings of candidate stallions presented for licensing at all German Warmblood horse-breeding associations in 2018–2020

BACKGROUND: Current studies on the health status of young German Warmblood stallions are lacking. AIMS/OBJECTIVES: To evaluate the prevalence of radiographic findings at licensing examinations of Warmblood candidate stallions and quantify the environmental influences on the distribution of recorded findings. METHODS: In this retrospective observational study, records of 1693 radiographic examinations performed on 1678 German Warmblood stallions presented for licensing in 2018-2020 were reviewed. Data were provided by all German Warmblood horse-breeding associations and their official veterinarians. The collection and storage of the records were performed using the German equine health database. Only the most recent examination per horse was included in the analyses. The influences of season of birth, age at licensing, year of licensing, and the evaluator on main radiographic findings were determined using generalised linear models with a significance level of p < 0.05. RESULTS: Overall, 71.4 % of the candidate stallions had remarks in their radiographic examinations protocols. However, the majority of the respective stallions had only single (49.8 %) or two (34.4 %) radiological findings. Main regions of the recorded findings were the proximal phalanx including the metacarpo-/metatarsophalangeal joint (25.3 %), the third metacarpal/metatarsal bone (20.3 %), the navicular bone (17.2 %), and the tarsus (17.2 %). Specifically, osseous fragments in the metacarpo-/metatarsophalangeal joint, contour changes of the proximal phalanx and the third metacarpal/metatarsal bone, and changes of the navicular synovial invaginations were documented. No significant influence of the season of birth, age at licensing, or year of licensing were found for the majority of radiographic findings. However, the distributions of several radiographic findings differed significantly between evaluators. CONCLUSION: The majority of German Warmblood candidate stallions presented for licensing in 2018-2020 had radiographic findings recorded. The clinical relevance of several of these findings in clinically healthy horses remains uncertain. Follow-up evaluations based on the data collected in this study could contribute to better risk assessment and are, therefore, recommended.