Summer has now arrived and with the recent heavy rain, warmth and sunshine, grass in paddocks is rich and continuing to grow rapidly. For our animals this is irresistible and they love the lush grazing. Be aware though, the sudden gift of sugary grass, be it long or short, is not suitable for all horses and ponies.

Serious, painful and life-threatening

Marketing initiatives such as Talk About Laminitis, by pharmaceutical companies and media initiatives over the past few years have done well to raise awareness around laminitis and contributory factors to the onset of this horrible disease.

Laminitis is serious, painful and life-threatening and can affect all members of the equine family: horses, ponies, donkeys and mules. It occurs when the laminae in the hoof, which suspend and hold the pedal bone in place in the hoof capsule, become inflamed and painful. In more serious cases this can cause the pedal bone to rotate or sink within the hoof capsule. In the UK, we typically see occurrences of pasture-associated laminitis peaking in the spring and autumn. Contrary to popular opinion, laminitis can occur year-round.

Acute laminitis is seen during the early stages of the disease, the horse will appear uncomfortable and show signs of lameness, however there are minimal changes within the hoof and prognosis is good if treated early. However, once the pedal bone has moved within the hoof, which leads to permanent damage, the horse is described as suffering from chronic laminitis and will require long-term, veterinary supervised, management.

Causes of laminitis

• Grass – good, lush grass and stressed poor grass (which develops fructans due to overgrazing or frost) can cause, or be the trigger factor.
• Over-nutrition – feeding of too much grain and sugary feed.
• Underlying hormonal disorder – Equine Cushings Disease (ECD) and Equine Metabolic Syndrome (EMS) can both be significant in the cause, and ongoing management, of the disease.
• Other non-related underlying disease – due typically to toxins circulating in the body. An example might be a mare not passing the afterbirth post-foaling, developing a uterine infection, then becoming toxic and developing laminitis.
• Concurrent drug use – Certain drugs, especially corticosteroids, can cause a bout of laminitis. This can also be a trigger factor in an animal with undiagnosed but underlying ECD or EMS.
• Excessive concussion from unusual amounts of exercise on hard ground.
• Stress – perhaps induced by transportation, hospital or environment changes.

Clinical signs

Clinical signs and presentation vary according to the severity of the bout of laminitis. Signs of an acute bout include:

• Lameness – this can be a pottery action at trot, reluctance to walk or inability to stand.
• Increased digital pulse to the feet and heat in the feet – both indicate inflammation.
• Other pain signs – sweating, rocking back onto heels, not wanting to eat, flank watching (as in a colic case). In severe cases the horse or pony may be unable to move, or lying down and finding it hard to stand. They may be sweating and leaning back on their heels, the typical ‘laminitic stance’.

In a more chronic case, signs also include:

• Rings around the hoof wall
• Prolapsing of the sole of the foot
• Short, shuffling action, which is much improved on soft ground – ‘a bit footy’

Diagnosis of laminitis is based on the clinical signs. Possible underlying conditions need to be established (and then treated concurrently) and whether causative or not are likely to be contributory factors. Radiographs of the feet are taken to establish if there has been any rotation or sinkage of the pedal bone due to the laminar inflammation and possible breakdown.

Treatment

Treatment is instigated rapidly to stabilise and prevent progression of the laminitis. Initial pain relief and management changes (padding feet appropriately and ensuring deep soft bedding of shavings) are important to make the horse more comfortable. Underlying hormonal and disease processes need to be addressed quickly. Rest, usually box rest, with controlled nutrition, is important whatever the cause. Each case is different, requiring tailored management and medication, depending on severity and underlying problems.

Be vigilant, particularly at this time of year, and monitor your horses, ponies and donkeys very carefully. Should you have any concerns that signs of laminitis may be present, please arrange a visit from one of our vets.

As always, if you have questions or want clarification on any matter regarding equine health, performance management, dentistry or dietary management do call the office for a chat with a veterinary surgeon – everybody in the Ballinger Equine clinical team is always happy to help.