Is Gastric Disease Really to Blame for Equine Behavior Issues?

In equine veterinary practice, gastric diseases, particularly Equine Gastric Ulcer Syndrome (EGUS), are often considered the primary cause of behavior problems in horses. However, correlation does not necessarily mean causation. Dr. Ben Sykes, a veterinarian specializing in equine gastric conditions, points out that a large proportion of horses, especially those in high-risk environments such as racehorses or top-level sport horses, have gastric ulcers without displaying behavior problems.

Common Behavioral Signs Attributed to EGUS:

It is common to associate gastric ulcers with various clinical symptoms in horses. Among these are weight loss, poor coat quality, aversive behaviors during riding, difficulty with girthing, and nervous or spooky behavior. However, these signs can also result from other conditions and are not always indicative of the presence of gastric ulcers.

Dr. Sykes reminds us that, while gastric ulcers are frequent (it is estimated that 50 to 70% of the equine population suffers from them), it is still difficult to prove that these ulcers are responsible for all the behavioral problems observed in horses. The mere presence of ulcers does not necessarily mean that the horse is experiencing behavioral issues directly caused by this condition.

A Broader Approach to Understanding Behavioral Issues:

Dr. Sykes emphasizes that when a horse exhibits strange or problematic behavior, it is essential to consider pain as a potential cause before focusing exclusively on EGUS. A comprehensive veterinary evaluation, including an assessment of lameness and oral health, is crucial. Horses may suffer from musculoskeletal pain or oral diseases, which can lead to behavior problems without gastric conditions being involved.

Moreover, several studies have suggested that there are links between EGUS and certain horse breeds, particularly top-level sport horses, such as show jumpers and racehorses. For instance, racehorses with gastric ulcers (especially glandular EGUS) were almost four times more likely to underperform than expected. Interestingly, top-level sport horses, who are often better managed, had lower rates of gastric diseases than national-level horses, which seems counterintuitive at first.

The Role of Chronic Pain and Learned Behavior:

Another important aspect of behavioral diagnosis is the concept of chronic pain and learned behavior. Horses are intelligent animals and can associate certain activities, such as saddling or preparing for riding, with pain. This association can lead to persistent behaviors even after the initial source of pain is resolved. Dr. Sykes stresses that, in such cases, the problematic behavior may not be related to current pain but rather to learned behavior that stems from past experiences of pain.

This is why a rigorous approach to diagnosis is essential. Once the source of pain—whether gastric, musculoskeletal, or oral—is identified, the veterinarian must also consider that the horse may have developed negative behaviors associated with this past pain. These behaviors may persist even after the physical cause is removed, requiring behavioral intervention in addition to medical treatment.

Steps in the Veterinary Evaluation:

When an owner consults for behavioral issues in a horse, Dr. Sykes always starts with a lameness exam. While this may seem unusual coming from a specialist in gastric ulcers, many of his horses end up with a diagnosis of lameness, which significantly contributes to the observed behavior. After confirming the potential presence of ulcers through gastroscopy, the veterinarian also conducts an oral exam to rule out other possible sources of pain, such as oral ulcers or dental problems.

After analyzing all these factors, the veterinarian can make a more accurate diagnosis. Sometimes a horse suffers from both gastric ulcers and musculoskeletal pain. This holistic approach allows for the identification and treatment of all contributing factors to the behavior.

Conclusion:

While gastric ulcers are common in horses, they are not necessarily the cause of all behavioral problems. When a horse displays behavioral issues, it is crucial to consider pain as the primary cause. A thorough evaluation and a broad approach to identifying potential causes will help pinpoint the underlying factors and improve the horse’s overall well-being. Dr. Sykes concludes by emphasizing the importance of stepping back and considering all potential sources of pain—not just EGUS—to make a quick and accurate diagnosis and enhance the horse’s well-being.