Researchers in Finland studied 152 horses that doctors thought might have inflammatory bowel disease (IBD), which is a condition where the stomach and intestines become inflamed and cause problems. The study found that horses with this condition often had trouble performing well, showed behavior changes, and had stomach ulcers. Interestingly, about half of the horses improved with treatment, and horses that had access to pasture did better. The researchers discovered that giving horses more time outside and better food might help more than just using medicine alone, suggesting that how we care for horses matters just as much as medication.

The Quick Take

  • What they studied: How to recognize, diagnose, and treat a stomach and intestinal disease in horses called inflammatory bowel disease (IBD)
  • Who participated: 152 horses in Finland that veterinarians suspected had IBD. These horses were examined in 2022 and had tissue samples taken from their intestines to check for inflammation
  • Key finding: About half of the horses (49%) showed good improvement with treatment. Horses that could spend time in pasture had fewer symptoms. Interestingly, the type of medicine used didn’t predict whether a horse would get better—but horses whose medicine was changed during treatment actually did worse
  • What it means for you: If your horse seems to have ongoing stomach problems or behavior changes, IBD might be worth investigating. The good news is that many horses improve with treatment, and letting your horse spend time outside and eat natural forage appears to be just as important as medication. However, this study was only done in Finland, so results might differ in other places

The Research Details

This was a retrospective study, which means researchers looked back at information that had already been collected. They gathered data from 152 horses that were examined by veterinarians in Finland during 2022 because the horses showed signs of possible IBD. The researchers collected information about each horse’s age, symptoms, physical exam findings, and results from tissue samples taken from the intestines (called biopsies). They also tracked what treatments the horses received and whether those treatments worked. The researchers used statistical methods to figure out which factors were connected to better or worse outcomes.

The key part of the diagnosis was a rectal biopsy—basically, the veterinarian took a tiny sample of tissue from the horse’s intestine to look under a microscope and see if there was inflammation. This is considered the gold standard way to confirm IBD in horses. The researchers then compared horses with different types of inflammation to see if certain patterns predicted better treatment response.

This study is important because IBD in horses is hard to diagnose and treat, and veterinarians didn’t have good information about what works best. By looking at real cases from actual veterinary clinics, the researchers could see what signs to look for, what tests help confirm the disease, and which treatments actually help horses feel better. This real-world information is more practical than laboratory studies because it shows what actually happens when veterinarians treat sick horses

This study has some strengths and some limitations. The strength is that it included a large number of horses (152) from actual veterinary clinics, making the results more realistic than laboratory studies. However, because researchers looked back at old records rather than following horses forward in time, some information might be incomplete or recorded differently by different veterinarians. The study was done only in Finland, so the results might not apply equally to horses in other countries with different climates or management styles. Additionally, the study didn’t have a control group of healthy horses to compare against, which would have made the findings stronger

What the Results Show

The most common signs that horses with suspected IBD showed were poor performance (68% of horses), nonspecific pain or discomfort (43%), and behavior changes like irritation or aggression (41%). About 63% of horses had actual intestinal symptoms like diarrhea or constipation. When veterinarians used ultrasound to look at the small intestine, 66% of horses had abnormal changes, and 37% had stomach ulcers.

When the veterinarians took tissue samples from the intestines, they found different types of inflammation: 35% had eosinophilic inflammation (a specific type of immune cell), 18% had lymphoplasmacytic inflammation (another immune pattern), 6% had neutrophilic inflammation (yet another type), and surprisingly, 40% had no inflammation at all even though they had symptoms. The inflammation was most common in horses aged 5-8 years.

For treatment, 68% of horses received medication and dietary changes. Glucocorticoids (a type of anti-inflammatory medicine) were the first choice for 73% of the horses that got medicine. About 49% of horses showed good improvement with treatment, while others showed partial improvement or no improvement. Interestingly, horses that had access to pasture showed significantly fewer symptoms compared to horses kept indoors.

Several other important findings emerged: behavior changes in horses were connected to the type of inflammation found in biopsies, suggesting that personality changes might be a clue that something is wrong with the intestines. When veterinarians changed a horse’s medication during treatment, those horses actually did worse overall—suggesting that switching treatments might not be helpful. Surprisingly, the specific type of inflammation found in the biopsy didn’t predict whether a horse would respond well to treatment, meaning you can’t just look at the biopsy and know if treatment will work. Only 12% of horses received an orthopedic (bone and joint) examination, which the researchers noted might be important since some horses might have joint problems that look like IBD symptoms

This study fills an important gap because previous research on equine IBD was limited, especially regarding treatment response in real-world situations. The finding that 49% of horses showed good improvement is encouraging and suggests that IBD in horses is not hopeless, unlike some other chronic conditions. The strong connection between pasture access and symptom reduction aligns with general knowledge about horse health—horses are naturally grazing animals and do better with access to pasture. However, the finding that biopsy results don’t predict treatment response is somewhat surprising and suggests that the current diagnostic approach might need improvement

Several important limitations should be considered: First, this was a retrospective study looking at old records, so some information might be missing or recorded inconsistently. Second, the study only included horses from Finland, so the results might not apply to horses in different climates or with different management systems. Third, there was no control group of healthy horses to compare against, making it harder to know if certain findings are truly abnormal. Fourth, the study didn’t follow horses long-term to see if improvements lasted over time. Fifth, different veterinarians might have diagnosed and treated horses differently, which could affect the results. Finally, the study couldn’t determine cause and effect—for example, while pasture access was associated with improvement, it’s not clear if pasture itself caused the improvement or if horses with access to pasture had other advantages

The Bottom Line

If your horse shows signs of poor performance, behavior changes, or digestive problems, it’s worth asking your veterinarian about IBD as a possibility. The evidence suggests that a combination of medication (often glucocorticoids) and dietary changes may help, with about half of horses showing good improvement. However, the strongest evidence suggests that providing pasture access, good quality forage, and exercise is important—possibly as important as medication itself. Don’t expect immediate results; give treatment time to work. If your veterinarian changes your horse’s medication, discuss whether this is truly necessary, as medication changes were associated with worse outcomes in this study. Confidence level: Moderate—this is real-world data from actual cases, but it’s limited to one country and doesn’t prove cause and effect

Horse owners whose horses show ongoing performance problems, behavior changes, or digestive issues should pay attention to these findings. Veterinarians treating horses with suspected IBD will find this information helpful for understanding what to look for and what treatments to try. However, these findings apply specifically to horses and should not be applied to other animals. People with horses in climates where year-round pasture isn’t possible should focus extra attention on providing high-quality forage and exercise alternatives during indoor seasons

Based on this study, horses that respond to treatment typically show improvement within weeks to months, though the study didn’t specify exact timeframes. About half of horses showed good improvement, suggesting that if a horse isn’t improving after several weeks of treatment, a change in approach might be needed. However, don’t expect overnight results—chronic intestinal problems take time to resolve

Want to Apply This Research?

  • Track your horse’s performance level weekly (using a scale of 1-10), note any behavior changes, record digestive symptoms (normal, loose, or constipated), and log daily pasture time in hours. This creates a clear picture of whether treatment is working and whether pasture access correlates with improvement
  • If your horse has suspected IBD, work with your veterinarian to maximize pasture time or create a pasture-like environment with constant access to hay, even during seasons when outdoor grazing isn’t possible. This single change showed the strongest connection to symptom improvement in this study
  • Create a monthly summary comparing your horse’s performance, behavior, and digestive health to the previous month. Note any medication changes and their timing relative to symptom changes. Share this data with your veterinarian to help guide treatment decisions and identify what’s actually working for your individual horse

This article summarizes research about inflammatory bowel disease in horses and should not be used to diagnose or treat your horse. IBD diagnosis requires examination by a qualified veterinarian and may include tissue biopsies. Treatment decisions should always be made in consultation with your veterinarian, who can evaluate your individual horse’s condition, medical history, and specific circumstances. The findings in this study are based on horses in Finland and may not apply equally to horses in other regions. If your horse shows signs of digestive problems, poor performance, or behavior changes, contact your veterinarian for proper evaluation and care.