Poor performance in horses is a very broad term and can include anything that falls short of a rider’s expectations for the animal’s physical abilities, said Tena Ursini, DVM, PhD, Dipl. ACVSMR, during her presentation at the 2024 Veterinary Meeting and Expo, held Jan. 13-17 in Orlando, Florida.

Ursini, a clinical instructor of equine sports medicine and rehabilitation at the University of Tennessee’s College of Veterinary Medicine, in Knoxville, links any case of subpar athletic performance in the horse to one of nine causes, estimating that 90% of cases involve the first one:

1: Lameness.

When presented with a horse displaying poor performance, Ursini first performs a musculoskeletal and lameness examination, takes a detailed history, and listens to the owner’s complaint. If the horse is lame on exam, the veterinarian needs to determine whether that lameness is significant enough to cause the performance problem. If it doesn’t appear to be, Ursini recommends taking a closer look at the other body systems.

2: Respiratory problems.

Exercise intolerance and equine asthma are two common respiratory-based hindrances to a horse’s athletic ability.

3: Muscular disease or injury.

Repeated episodes of exercise-induced rhabdomyolysis, more commonly known as tying-up, can seriously hinder a horse’s athletic performance, she said.

4: Neurologic deficits.

An array of potential problems can affect the horse’s nervous system, ranging from systemic conditions such as equine protozoal myeloencephalitis (EPM) or equine degenerative myeloencephalopathy (EDM) to localized lesions in the spinal cord resulting from cervical facet osteoarthritis or cervical stenotic myelopathy (compression of the spinal cord).

5: Cardiovascular restrictions.

Although comparatively rare, heart problems sometimes get in the way of horses’ athletic careers. Ursini said endocarditis (inflammation of the heart valve) is the most common heart problem that causes poor performance but, in general, cardiac problems manifest as a progressive decrease in stamina despite regular training.

6: Gastrointestinal troubles.

A horse that’s girthy, has an inconsistent appetite, and is hard to keep weight on makes her suspicious of gastric ulcers.

7: Reproductive or behavioral challenges.

“You need to rule out other physical problems before turning to the reproductive organs as a potential source of pain that limits athletic capacity,” Ursini said. However, an ovarian tumor, especially a granulosa cell tumor, could cause aggressive mare behavior.

8: Lack of fitness.

“Many owners overinflate the true athletic fitness of their horses,” she said. “Just hacking around five days a week does not guarantee that your horse has the strength or stamina for any particular purpose.” To measure your equine athlete’s fitness, she recommends using a heart rate monitor while riding to determine how long it takes for your horse’s heart rate to return to 60 beats per minute immediately after exercise—the longer this takes, the less fit the horse is.

9: Lack of talent.

“This one applies to both horse and rider,” said Ursini. “If an equestrian has Olympic show jumping ambitions but their ride is a ranch-bred Quarter horse, that horse will technically be a poor performer for that particular rider’s expectations.”

Take-Home Message

“After ruling out physical causes for your horse’s poor performance, take a realistic look at his and your own athletic potential,” says Ursini. “Consider your equine partner’s current fitness level, age, breed, and conformation to determine if your riding goals are achievable with that particular horse.”