Ulcers in Endurance Horses

One subject that seems to come up less often than others is the topic of ulcers in endurance horses. One vet I questioned, went so far as to say that 'If a horse has ulcers - he shouldn't be doing endurance.' Fair enough - I do understand the logic in the statement.
However that outlook isn't addressing the formation of squamous ulcers or sores during a competitive event. In a recent study on upper level endurance horses, it was shown that the prevalence of gastric ulcer syndrome was 93% during the competitive season and 48% during the off season.

The study took place at the National Veterinary School in Toulouse France, where they tracked 30 individual equines that were competing at the 90km through to 160km range.

Y. TAMZALI*, C. MARGUET, N. PRIYMENKO† and F. LYAZRHI‡
Equine Internal Medicine, Ecole Nationale Vétérinaire; †UMR 1089 Xenobiotics, INRA, National Veterinary School; and ‡UMR181
Experimental Physiology and Toxicology, INRA, National Veterinary School, Toulouse, France.


"Sample population
Endurance horses competing in national or international rides
within professional teams were selected and submitted to 2
gastroscopic examinations. A total of 30 horses aged 7–14 years
entered the study. They were 6 females and 24 geldings with a
majority of Arab breed (20) followed by Anglo-Arabs (9) and one
cross breed. Eight horses were kept permanently on pasture and 22
were housed in a mixed environment (stall and pasture). All horses
were fed similarly: hay distributed ad libitum and concentrate twice



This high prevalence of gastric ulcers in elite endurance horses is similar to the rates of ulcers in other athletic horses and could be an important cause of poor performance," relayed Tamzali.

Two other important findings Tamzali uncovered were:

1. Horses kept on pasture showed significantly higher "ulcer scores" than the horses housed in a mixed environment (the group of horses kept on pasture had a high starch diet due to added concentrates); and
2. A positive correlation existed between "gastric score" severity and ride distance: the longer the ride, the more severe the score.

"These results strengthen those obtained by another research group and underline the fact that amount of starch fed per day or per meal is a very important factor in development of ulcers," added Tamzali.

The complete article was published this fall in the Equine Vet Journal.
Abstract here:



The findings are significant - in that the overall prevalence of Equine Gastric Ulcer Syndrome (EGUS) is distinctly high, showing that it's a safer guess that more endurance horses suffer from this than we'd like to think. There is limited information on the preventation and maintenance of EGUS , in endurance. The barrel racing and track racing communities do appear to have much more 'laymans' knowledge on the subject.

The standard operating procedure is a course of Ulcerguard to get control and manage an onset of ulcers- which is costly and a reactionary methodology (the horse already has ulcers)

Looking for a way to decrease the probability of EGUS is a slighty different matter. The recommendations are for horses to have more feedings throughout the day to manage acid levels in the stomach. This of course is commonly known for a variety of reasons, the main being of course - a horse is a grazing animal. The other option suggested is for alfalfa to be a portion of the diet, as the extra calcium can be of significant value in aiding with the formation (or non formation) of acids. As well as a dose of Ulcerguard before a traumatic event (trailering to a ride and so forth)

Another article here: