Cover Story | GI Disease

Integrate nutrition with medical management for IBD

By Marie Rosenthal MS

Nutrition must be integrated with the medical treatment of equine inflammatory bowel disease (IBD) to effectively manage the condition, according to equine nutritionist Tommaso Danese, DVM, PhD, ECVCN Res, of the University of Parma, in Italy.

However, monitoring is complicated because it can be hard to tease out which dietary change or treatment is helping the horse when too much is done at once, Dr. Danese admitted during a virtual presentation at the ACVIM Forum 2026. “The clinical scenario is complicated,” he added.

Often, nutritionists are presented with a horse that is performing poorly with some weight loss and intermittent colic. “We don’t know the case. We don’t have a diagnosis. The findings do not give us a clear answer,” he said. Often, veterinarians are left treating the “uncertainty.”

Dr. Danese walked veterinarians through some of his considerations when faced with a horse with IBD, which he described as a heterogeneous group of chronically inflammatory intestinal diseases. Key characteristics typically include chronic intestinal inflammation, malabsorption, weight loss, diarrhea, recurrent colic, and/or poor performance, though some cases may be subclinical.

“Different phenotypes of the disease require different feeding compromises—and most of the time, medical compromises. And I think this heterogeneity of the pathology is what makes this complicated to manage,” he said.

There is no one-size-fits-all management—medical and dietary implementations may need tweaking. However, the basic “recipe” for IBD is to modify forage, reduce concentrates and starch, consider fiber, increase fats and avoid certain foods that might be contributing to the inflammation. Reducing inflammation will enable the gut to heal, but when changing the diet to reduce inflammation, one must also provide the energy the horse needs and ensure it is still receiving all required nutrients.

A mainstay of nutritional changes is avoidance or a reduction of potential intestinal stressors. “We tend to modify forage, we reduce concentrate because we want to reduce starch, and we increase the fat to avoid losing energetic power. We don’t want to dilute the energy too much,” he explained.

“But excessive restriction can compromise efficacy because a horse with IBD still needs energy, protein, vitamins, minerals, trace minerals and water. If we do fully remove 1 ingredient, it does not mean we’re working in the direction of the horse getting better,” Dr. Danese said.

One of the most debated items gluten avoidance, but evidence regarding its value in horses is slim. IBD is not celiac disease, he insisted. “Evidence suggests that there is still a heterogeneous picture, and there is not a clear universal gluten-driven mechanism for IBD [in horses],” he explained. “Some horses may improve with gluten exclusion—they clinically do better without putting gluten in the diet—but this does not mean that the IBD horse requires a gluten-free diet,” he said.

Although more research is needed, gluten exclusion might be worth a try. However, Dr. Danese said that gluten exclusion should not always be automatically recommended as a baseline dietary exclusion, but it might be useful in select cases.

Given the lack of standardized dietary protocols, Dr. Danese suggested that clinicians think of the horse’s nutritional needs as a food pyramid, similar to the one used by the Department of Agriculture for human use, with forage as the base and supplements at the top.

“We want to reduce gastrointestinal stress. We want to start slowly, but we need to meet requirements for energy, protein, vitamins, micronutrients and trace elements because malabsorption is the main issue in this pathology,” he said.

Forage
“Forage is the foundation of the diet,” Dr. Danese said. Horses should have up to 2% of their body weight in dry matter or forage. Remember that some haylages or forages can have up to 14% moisture content. It is important to select the forage that is digestible, hygienic, and physically tolerated, as well as clinically appropriate for a horse, he added.

This typically means a combination of short- and long-stem forage, and perhaps some pelleted product. The physical form of dry matter matters because the horse’s GI tract must be able to tolerate and digest it without increasing the irritation in the gut.
Fiber is important, but it needs to be a combination of soluble and insoluble, he said.

Fats, starches and concentrates
Starch and concentrates also need to be managed, he said. The maximum starch requirement in a healthy horse is about 1 g starch per kg of body weight per meal, or 2 g starch per kg of body weight per day. However, the requirements should be lower in horses with IBD, depending on the severity of the disease.

“Starch is not just about quantity; it’s also about digestibility,” Dr. Danese said. Starch may increase osmotic and fermentative stress associated with impaired small intestinal function.

Reducing starch lowers energy, which is undesirable, so veterinarians frequently add fats. Again, digestibility and tolerability weigh into the selection of fats—usually corn or linseed oil, according to Dr. Danese.

“Fat is definitely one of the most important things to consider because it can help us as an energy source,” Dr. Danese said. However, tolerability of oils differs among horses, and fat supplementation increases the oxidative load, so vitamin E must be adjusted accordingly, he explained.

Regardless of the fat selected, it should be introduced gradually and adjusted to the horse’s tolerance, he suggested, because high levels of fat decrease the speed of gastric emptying.

Protein
Protein must be maintained at sufficient levels to support muscle and body condition, he explained, but it is advisable to avoid novel protein sources. “We want to tackle a good protein intake, but we want to avoid antigen load,” Dr. Danese said.

Supplements
People love supplements, as evidenced by the $218 billion they spend on them each year. Some supplementation is necessary when changing a horse’s diet, but it should be an adjunct to the diet. Equine nutritionists will frequently supplement vitamin E and trace nutrients to support antioxidant and immune function.

Another consideration is microbiome modulators. There are many on the market, and they work in different ways—prebiotics, postbiotics and synbiotic probiotics. Classic yeasts work well, he said. “They should not be considered as primary care, but they’re supportive of a good diet and good medical therapy,” he explained.

The reality of treatment
Often, the equine nutritionist will be faced with what Dr. Danese calls “the most difficult horses to manage.” These are the horses that are still in competition, for which IBD is suspected but not confirmed.

“They ask us for a diet to manage the suspected inflammatory state of the small intestine when the diagnosis is not certain, but they still want to meet the sporting requirements,” he said. “It’s tricky because it’s not possible to do everything.”

One has to maximize the use of highly digestible forages and reduce starch while maintaining the competition horse’s energy requirements. Often, owners want to avoid gluten, which isn’t always advisable. “It’s difficult to propose a dietary plan that is not extremely expensive and that allows the horse to perform at the level that’s required without gluten,” Dr. Danese said.

“This forces us to tackle our expertise in balancing diets, playing with different ingredients and different concentrates, and [getting] really deep into the composition of the concentrates and understanding how things are done. And in my opinion, this is the most complicated kind of thing because we don’t have a clinical diagnosis, and it’s really technical, so it takes time, and it’s not always clear if the change works as well,” he said.

Owner compliance is an important determinant of whether the plan will be successful because smaller, more frequent meals improve tolerance, yet owners often cannot provide them. Yet, a horse allowed to graze naturally will eat on and off all day, and an IBD horse allowed pasture during healing will get clinically better.

However, most competition horses are stabled for 8 to 16 hours a day, and if they have turnout outside a paddock for a couple of hours, there is no grass.

“This is the main reason why this pathology is so complicated to manage, because we don’t have the tools to deal with management issues,” Dr. Danese said. “We can do the best and the most precise diet, but if the owners can’t or don’t want to do it, it’s difficult to manage the cases.”

So, it is important to work with owners and explain why compliance is essential to the successful scientific and ethical management of the horse. “We want to give a diet that allows the best life for the horse, considering also the physical restraints that the horse can have.”

Meal frequency is important, as is the physical form of the feed. A small hay net or other prolonged feed technique might be useful, especially in a horse that is stabled for a good part of the day.

“In my opinion, nutrition should be flexible because this is a complicated therapy that takes time to improve,” Dr. Danese said, “and we need to reassess the horse, not just on the paper, not just seeing the diet again and changing, but we need to visit the horse to see the horse, to see the clinical variability, to see the exam, to see the BCS [body condition score], to see if the phenotype is changing.

“Because sometimes, in time, the phenotype can change and we hope to improve it.” MeV