Last Updated on April 4, 2022 by Allison Price
Although the term “epiphysitis”, is often used, it is more accurate to call it physitis. It is an area that has become inflamed if it ends with the medical term “-itis”. The medical term for bone growth plates is physis. It is this area that gets inflamed and hence the name “phys-itis”.
Physitis can be described as a developmental orthopaedic disorder. Many other diseases fall under the umbrella developmental orthopaedic disorders, including osteochondritis Dessicans (OCD), wobbler Syndrome and angular leg deformities. All of these problems can occur in the same animal, but not all.
Physitis is a common disease in foals that are heavy and fast growing and can be found in thoroughbred as well as sport horse herds. Foals receiving a lot of hard feed are more likely to get it. It is also more common for foals who have been fostered by cob-type foster mares, according to the authors.
This is due to the over-compression or compression of the spongier part of the bone’s growth plate. Inflammation is the main cause, but it can also lead to changes in bone growth that will cause permanent damage.
General physitis can be quickly recognized by skilled stock personnel and doesn’t cause lameness. Additional investigations like x-rays and other tests are not necessary.
How does it look?
Physitis is a painful, hardening, and warm feeling of swelling around the fetlock, knee, or at the level the growth plate of long bone cannon or forearm. When the growth plate/physis is touched, there is usually a pain response. To rule out traumatizing causes of swelling, such as knocks to a joint, x-rays are sometimes taken. In cases of physitis, there is no swelling of the joints.
The most common location for this problem is in the fetlock, which is usually located just above the joint. Photo one
Also, the knee is a common spot. See photo 2 below. Although the hock could also be involved, this is rarer.
How to prevent physitis
The best way to avoid physitis in foals is to provide a balanced diet that supplies all essential nutrients for growth and does not cause them to become overweight. It sounds simple!
Why is this so popular? Even the best stockmanship and dietary management can lead to physitis. It would appear that there is a genetic predisposition. Some horses gain weight faster than others, and some horses may be more sensitive. Foster mares are likely to produce rich milk in large quantities. Many mares can produce very rich milk. It is hard to control the quality of milk. It is easier to increase the quality of milk than to lower its value. While limiting the nutrition of mares may have an effect, it is not as easy to decrease their value. It is important to consider the reproductive status of the mare. Is she still in foal? The next pregnancy should not be compromised.
It is possible that sub-optimal dietary intakes of essential vitamins and minerals can also have an impact. The most important nutrients are zinc, phosphorus and copper. It is important to regularly analyze hay and grass, as well as concentrate.
Management/treatment of physitis
Two key components are required to treat physitis: diet restriction and box rest. Most cases do not require medication, however, if the foal is unable to walk or has a limp, your vet may prescribe anti-inflammatory medication.
Box rest is a way to limit exercise and active compression, especially when the foal is moving around. Box rest can vary from one case to the next, but it could be anywhere from 2 weeks to 2 months. This is to reduce the foal’s bodyweight. The foal is still developing, so you must provide nutrition and vitamins to help it grow. Calories should be limited, but minerals like calcium and phosphorus should be given to maintain normal musculoskeletal development.
Foals with physitis can be treated early and the foals will have a good chance of being sold and racing.
I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!