"What is OCD? How Does the Condition Affect Horses?

"What is OCD? How Does the Condition Affect Horses?

Health & Safety

OCD is a condition that affects horses in varying degrees, and it's one that is far from being easy to understand or to diagnose. Deciding on treatments can be difficult but then so is being given an accurate prognosis to the condition. Many vets have to admit the condition is anything but straightforward from the word go.

The condition which is officially called “osteochrondrosis dissecans” can be crippling to some horses, whereas in other horses the condition may only affect them in a small way and very often the horse will remain sound showing no signs of lameness whatsoever. For this reason, it is a condition that's extremely hard for vets to accurately identify without x-raying joints or performing keyhole surgery on the affected joint.

How and When Does the Condition Occur?

The condition is first seen to develop in foals and starts before they even reach twelve months of age. The result of the condition usually leads to different types of bone and joint issues later on in the horse's life and in some horses, this can be crippling whereas in others, not so at all.

As a foal's bone growth develops a process known as endochondral ossification occurs. This is when cartilage is converted to more solid bone. This natural process of growth fails to fully function in foals affected by the condition known as OCD. As a result areas of damaged cartilage develop in their joints – this leaves the underlying bone prone to injury because it has been weakened.

However, because cartilage and bone are still growing at a year old and beyond, some of the damage does heal naturally. Problems really start when cartilage no longer transforms to bone, and is when any natural healing process becomes very limited.

The result is any loose fragments or flaps of cartilage that have not had a chance to attach correctly, will eventually lead to irritation. This in turn, causes inflammation and swelling to any joints affected by the condition but this normally occurs later on in the horse's life. The whole syndrome is referred to as Osteochondrosis, the dissecans being the fragments or flaps of cartilage bought about by the condition that have failed to naturally transform to more solid bone.

The Signs to Look Out For In Horses

  • One of the most obvious signs you'll notice is an enlarged and swollen joint. The swelling is due to extra fluid forming because of the inflammation

  • Typically, you may see a bog spavin develop which is a distended main hock joint. This often looks a lot worse than it actually is, but it is always recommended to have the problem looked at by a qualified vet

  • The real problems are often not that obvious, and this is especially true when other joints namely stifles and any of the four fetlocks become swollen due to the condition

  • Horses with the condition may show signs of lameness but this can well vary from day to day. One day the horse will be sound and the next, they are hopping lame

  • You may notice your horse takes on an awkward stance and they show poor impulsion and unusual stiffness which reduces activity

  • The other thing you may notice is your horse may not seem so keen to lie down, and that when they do, they struggle to get back up again

Diagnosis & Treatment of the Condition

Clinical signs of the condition are often quite subtle and difficult to pick up on. However, x-rays will normally confirm whether a horse is suffering from the condition. With this said, an -ray only shows bone clearly and not cartilage. This is why a specific surgery known as arthroscopy (keyhole surgery) is recommended.

Keyhole surgery to an affected joint will give a much clearer picture of what is going on within a joint. It will also show just how much damage there is to a joint. In this way any loose fragments can be safely removed to alleviate inflammation and help clear up an affected joint. However, surgical intervention may not always be necessary even though it is very effective. This is especially true if a horse does not show any lameness due to the condition.

Where foals are concerned, the condition appears and then can heal itself quite naturally and quickly. A few foals do respond well to rest and a correctly balanced diet when the condition rears its ugly head. However, the most difficult to spot is often referred to as being clinically “silent”.

In this instance, the condition only shows up in older horses when they undergo an x-ray examination prior to being purchased. The question many potential buyers and sellers have to ask themselves is whether it makes sense to have a completely sound horse undergo surgery or to ignore the condition and hope the horse will stay sound? The other question being would it a good idea to go ahead and buy a horse that has the condition?

Secondary Problems in the Older Horse Due to OCD

As horses get older and are known to suffer from OCD problems, the more likely they are to go lame. On top of this, continued and long-term inflammation in any joint will potentially lead to the horse suffering from arthritis. As such, vets tend to treat the condition depending very much on all the factors involved in each individual horse. This includes the degree of lameness involved as well as where the condition has occurred and lastly it's severity. The other consideration which has to be taken into account is a horse's age.


Horse owners worried about OCD and who think their mounts may be suffering from the condition, should contact their vet and discuss the problem in-depth with them. There has been a massive advancement in surgical interventions when it comes to joint problems found in horses, and vets have successfully used joint medication on many affected horses with great success. You may find your vet recommends you get in touch with an equine orthopaedic specialist in order to start an effective treatment, or whether surgery would be the best route to take to solve an OCD problem.

Newsletter icon
Get free tips and resources delivered directly to your inbox.


Pets for StudWanted Pets

Accessories & services


Knowledge Hub


Support & Safety Portal
All Pets for Sale