Dorsal displacement of the soft palate in 92 horses during high-speed treadmill examination (1993-1998).

The study investigated the occurrence of dorsal displacement of the soft palate (DDSP) during high-intensity exercise in racehorses, how it can be diagnosed, and the effectiveness of various treatments. The majority of the horses displayed an improvement in race performance after being diagnosed and treated for the condition.

Methodology

• The study involved a retrospective analysis of 92 racehorses, 74 of which were Thoroughbreds and 18 Standardbreds.
• The researchers reviewed the horses’ history, which included clinical, race data, treatment details, and video records obtained from rest and high-speed treadmill (HSTM) endoscopic examinations.
• Only the data from horses with verified DDSP (confirmed via HSTM examination) and who completed at least three starts before and after HSTM examination were included in the performance-outcome analysis.
• The study also looked for associations between various independent variables such as historical findings and endoscopy results, and the performance outcome.

Results

• About half of the horses diagnosed with DDSP showed ‘uncomplicated’ displacement of the palate. The rest either had an associated upper-respiratory abnormality or displacement after swallowing.
• Intriguingly, abnormal upper-respiratory noise, a potential symptom of DDSP, was not recorded during HSTM exercise in many of the horses diagnosed with the disorder (62%).
• None of the analyzed variables recorded during resting or HSTM endoscopy showed a significant association with race performance.
• Following diagnosis and treatment, 64% of the horses showed improved race performance, as indicated by increased average earnings per start.

Conclusions

• Many of the horses diagnosed with DDSP during HSTM endoscopy did not show any previous signs of abnormal upper-respiratory noise. Furthermore, in 80% of the cases, no structural abnormalities were observed during a resting endoscopy.
• The HSTM examination proved to be a useful tool for diagnosing DDSP and understanding how it affects individual racehorses.
• However, DDSP’s manifestation was found to differ from horse to horse, with many having another associated upper-respiratory abnormality. The findings suggested that a single common treatment strategy may not be applicable or effective for all horses suffering from DDSP.
• The study concluded that both surgical and medical treatments had the potential to improve race performance post DDSP diagnosis.
• The study also highlighted that neither resting nor HSTM endoscopy findings could effectively predict race performance.