How Starch Affects Horses' Performance

By: Dr Rosie Alcorn BVSc PG Cert VPS Cert AVP MRCVS

Latest Research on Low-Starch Diets and Ridden Performance in Sport Horses

In late October, new research published in the Journal of Veterinary Internal Medicine examined the effects of low-starch diets on pain scores and gastric health in sport horses.
Equine Gastric Ulcer Syndrome (EGUS), a condition affecting 17–58% of sport horses, has been linked to general performance issues, but research on its specific impact on under-saddle performance has been lacking. This recent study aimed to address this gap by evaluating how diet affects ridden behaviour and pain management in horses.

Study Overview

Nine show jumpers, previously fed a high-starch diet (29% starch, 2.5% sugar, 14.5% cellulose, and 11% protein) for over 18 months, were selected for this study. The horses underwent a clinical exam, a gastroscopic assessment, and a standard exercise test to evaluate pain scores, stride regularity, hindlimb impulsion, and jump energy using a ridden pain ethogram scoring system and data from an iJUMP saddle.

Findings

Initially, eight of the nine horses showed signs of gastric ulceration. The horses were then switched to a low-starch diet (11% starch, 5.5% sugar, 12% cellulose, and 11.5% protein) and reassessed after 12 weeks. The second evaluation showed a significant reduction in gastric lesions, with two horses achieving complete ulcer healing. Performance testing indicated improvements in total jump energy, post-jump balance, and canter regularity for specific jumps. Overall, pain scores for ridden work decreased significantly by week 12 on the low-starch diet, with reductions in head tilting and slow gait.

Conclusion

This study highlights the impact of low-starch diets on equine gastric health and suggests that dietary adaptations may improve ridden performance without compromising athletic ability. Although more research on a larger group of horses is needed, the findings support lower-starch feeding for horses with EGUS to reduce gastric ulcers and enhance comfort under saddle. If your horse shows signs of gastric ulcers, consult your veterinarian for diagnosis. For EGUS-diagnosed horses, this study emphasises the importance of low-starch diets. For assistance with diet formulation, please feel free to contact us.