Equine glandular gastric disease (EGGD) can negatively affect the health and performance of sport horses. The pain caused by this condition often prevents affected horses from performing well in competition, leading to welfare concerns and a negative economic impact for owners and trainers alike due to cost of treatments and loss of training and competition time. In addition to medical treatment led by a veterinarian, most horses with EGGD benefit from nutritional and management changes to support treatment and promote long-term ulcer prevention.

Alfalfa vs. Concentrate for Horses with EGGD

To observe the effects of management on EGGD, Samy Julliand, PhD, director of animal nutrition research at Lab to Field, in Dijon, France and his coauthors studied 77 French trotters, ranging from 2 to 3 years old, from four different training centers. The researchers selected these training centers because they had comparable training and feeding management—all horses in the study exercised five to seven days per week, with one to three days of fast work on a track.

At each center, researchers divided horses into two groups based on baseline ulcer scores, age, and sex. They then randomly assigned each horse to a control group to stay on their usual diet throughout the study or an alfalfa treatment group that had half their concentrate feed replaced with alfalfa pellets. An outside blinded veterinarian performed gastroscopy on each horse on Days 0, 21, and 42 of the study, scoring glandular ulcers on a scale of 0 to 4, with 0 being no ulcers.

On Day 0 the researchers saw no significant relationship between horses’ overall energy intake (how many kilocalories or megacalories) in their diet and EGGD, but they noticed horses that consumed more simple sugars received lower scores. “Prior to the study, based on previous knowledge, we had hypothesized that the higher the carbohydrate content of the diet, the higher the glandular scores,” said Julliand. “We were surprised to observe that this was not the case in this study … and, on the contrary, that simple sugars were associated with a lower prevalence of glandular ulcers. It’s possible that this is associated with the microbiota favored by these substrates.” Julliand and his team plan to further investigate this aspect in the future.

Also on Day 0, the veterinarian found glandular ulcers scoring at least 2 in severity in 13 of the 77 horses. On Day 21, three of the 31 control horses had glandular ulcers with a severity of at least 2, while none of the 28 horses in the alfalfa group had ulcers with a severity of 2 or greater (some were unable to participate in this gastroscopy). On Day 42, 12 control horses and four alfalfa group horses had glandular ulcers.

The researchers noted a positive relationship between feeding alfalfa pellets and a decreased incidence of EGGD by Day 42 of the study. They believe this was due to the overall decrease in starch consumption when alfalfa pellets replaced half the concentrates and the high calcium concentration of alfalfa, which buffers acid production in the gastric environment.

Managing Horses With EGGD

While the researchers do not have exact management recommendations for owners managing glandular ulcers in horses, the results helped them begin to form possible advice. “Even if the optimum rate of integration and form of presentation have not yet been determined, dehydrated alfalfa could be integrated into the rations of horses at risk for EGGD,” said Julliand. “It could be beneficial for their health, without impairing the performance of athletes.”

Future Glandular Ulcer Research

Julliand and his team plan to repeat this study and include a medical treatment group as well as a larger number of ulcerated horses. He said they also hope to further explore the diet-microbiota-gastric health relationship because this knowledge might be useful for developing new ways to prevent or treat glandular ulcers in horses.

Take-Home Message

Researchers are confident a strong relationship exists between a horse’s dietary management and incidence of EGGD. Julliand said more work needs to be done on the relationship between gastric microbiota, gastric health, diet, and management, but that he and his team believe dehydrated alfalfa shows promise in preventing glandular gastric ulcers.

The study, Effect of Diet Composition on Glandular Gastric Disease in Horses, was published in the Journal of Veterinary Internal Medicine in August 2023.