Joint Health: Problems and Prevention
By Clare MacLeod MSc RNutr, Independent Equine Nutritionist
There is a long history of fascination with the horse’s athletic ability, which is used in both sport and leisure. Physiologically, horses are supreme athletes and much more naturally talented than humans. But this athleticism means that they are prone to musculoskeletal problems, especially in their joints, and domestication and breeding for specific traits has probably enhanced the likelihood of problems. Joint problems include injuries such as sprains and developmental orthopaedic diseases (DOD) in young horses, but the most common cause of joint lameness is osteoarthritis (OA), and one veterinary survey showed that 60% of lame horses had OA.
What goes wrong?
Joints – also called articulations, hence the term arthritis – are where bone ends meet and are joined together by a fibrous joint capsule and connective tissue. The ends are covered in smooth cartilage to enable them to glide smoothly, allowing movement. If damage occurs, the resulting inflammation causes damage to the cartilage, which, due to its limited repair capabilities, can become thinner and roughened. Eventually, the underlying bone is also affected, at which stage the condition is described as OA. Inflamed bone produces more bone in an attempt to heal, so bony spurs and overgrowth can result.
Joint problems include:
• Injuries including sprains (ligament damage)
• Developmental orthopaedic disease (DOD) including OCD and bone cysts
• Arthritis (joint inflammation)
• Septic arthritis
• Osteoarthritis, a degenerative condition which is often an end point of one or more of the above problems
How exactly OA occurs isn’t fully understood, and a good description is given by orthopaedic vet and researcher Dr C. W. McIlwraith, when he states it is ‘a complex interaction of biologic and pathologic processed highlighted by eventual degradation of articular (joint) cartilage and associated pain’.
A variety of factors increases the risk of OA, including a genetic predisposition, poor nutrition e.g. a unbalanced diet during growth, obesity, excessive work (exercise), injury, inappropriate surfaces, and old age. Classic signs of OA are pain and stiffness, although early stages can occur without overt symptoms. Over time range of motion is reduced and there may be swelling.
How to prevent and manage
Joint injuries, DOD and OA are impossible to prevent, but there are certain strategies that seem to reduce the risk. Starting early is the key to reducing the risk of joint problems:
• Select breeding stock carefully to minimise genetic susceptibility
• Feed a balanced diet to growing youngstock, taking extra care with energy and protein balance, mineral intake, starch intake and ensuring slow gradual growth
• Use a progressive and carefully planned exercise regime, never working the horse harder than its current state of fitness
• Intervene as early as possible with injury
• Feed a balanced diet with particular emphasis on mineral balance and a healthy bodyweight
• Check what you are feeding and that it contains effective levels of ingredients to support joints
There is no cure for OA and all that can be done is to make the horse as comfortable as possible for as long as possible, and perhaps limit further breakdown, with good management, appropriate dietary nutrition, plenty of movement, veterinary intervention including oral and intra-articular medication.