Behavioral and cardiac responses to a model startle test to assess retired Thoroughbred racehorses for equestrians.

The research focuses on a practical procedure for assessing the suitability of retired Thoroughbred racehorses for equestrian sports and leisure activities. It seeks to determine whether horses with reactive temperaments to a standardized startle test would show improved responses following transition training.

Research Objectives and Methods

• The objective of the study was to develop a practical procedure to assess the readiness of retired Thoroughbred racehorses for equestrian sports. This was done by looking at the horses’ behavioral and cardiac responses to a startle test before and after a three-month transition training period.
• The startle test involved applying a plastic bag to the neck area of the horse, to which the animal was expected to react. The responses to this test were then measured and recorded.
• In total, twelve retired Thoroughbred horses (6 males and 6 females) were involved in the study. Their average age was approximately 4 years, and the average body weight was around 465 kg. With these twelve individuals, an a priori power calculation denoted a power requirement of 80%.

Key Findings

• The study found that there was a significant reduction in the horses’ behavioral scores, peak heart rate, and response duration after the training period when compared to their pre-training scores. These results signified a drop in the overall reaction intensity of the horses to the startle test after completing their transition training.
• Nonetheless, 25% of the horses (3 out of 12) still retained a behavioral score of 2 or above post-training. These horses also showed significantly higher peak heart rates and longer response durations in comparison to those with a behavioral score below 2.
• Upon analysis of gender differences, it was discovered that female horses showed a significant increase in the root mean square of successive differences between normal heartbeats after their transition training period.

Conclusions

• The research contended that transition training can improve the suitability of retired Thoroughbreds for equestrian sports. This was based on the observed improved responses of the horses to the startle test post-transition training.
• However, despite the observed overall decrease in reaction intensity, a notable proportion of the horses still retained a relatively high behavioral score even after the training. This suggested the necessity of further studies to optimize the transition training protocol for these retired Thoroughbreds.