Dr Amber Whitmarsh from the Kingston Veterinary Group reveals the many diverse causes of this potentially crippling equine disease
It is a common misconception among owners that laminitis is simply a result of obese ponies overeating lush grass, and only ponies not horses can develop this condition. Resent research has shed new light on the causes of laminitis, and in this editorial we highlight when horses and ponies are at risk of developing the disease.
Rich Grass: The type of grass and the sugars it contains is more important than the amount of grass consumed in the development of laminitis. Many horses and ponies are kept on pasture which was once used for grazing cattle. This land may have been heavily fertilised and re-sown with particular species of grass which are not suitable for equines.
Pasture Conditions: The risk is highest when grasses are growing rapidly and contain large amounts of simple carbohydrates such as sugars, fructans or starches. These times occur when there is mild weather and heavy rainfall such as in the spring, early summer and autumn. They can also accumulate when pastures have been stressed during periods of frost or overstocking. The amount and the type of carbohydrate ingested from the grass are very important in the development of laminitis. Horses breaking into feed rooms and consuming large amount of feed can also lead to laminitis via a similar pathway of carbohydrate overload.
Underlying Disease: Laminitis can also result when an animal is sick or has an underlying condition. Due to the hormonal changes seen in Equine Cushings Disease, there is an increased risk of laminitis which is very difficult to control. All horses and ponies that develop laminitis without an obvious cause should be tested to rule out this condition.
Obesity and high blood insulin levels are associated with increased risk of pasture-associated laminitis. Often at-risk horses are “good doers” and have increased fat deposits over their top lines. This gives rise to the “cresty neck” that is typical of horses and ponies with equine metabolic syndrome.
In cases where a mare fails to fully cleanse after foaling, an infection in the womb can quickly develop. Toxins are then released into the circulation which leads to a cascade of events resulting in laminitis.
Dependent Laminitis and Farriery: Occasionally, laminitis can develop in a limb where the opposite limb is painful for reasons such as a foot abscess or tendon injury. The insult to the injured limb causes the opposing limb to take more weight than it normally would and can result in laminitis.
Delays between foot trimming are an important cause of stress and damage to the hoof laminae. Regular visits by the farrier will also pick up the early warning signs of laminitis.
Medicines & laminitis
Certain drugs, primarily corticosteroids, can in some cases result in laminitis. Veterinary surgeons are particularly careful about their use, although in most cases the benefit of treating the horse with corticosteroids outweighs the very small but potential risk. If you suspect your horse or pony has laminitis then contact your vet as soon as possible.
Get in touch
If you have any questions about laminitis or would like some advice please contact one of our Equine Team: Keith Jones BVSc MRCVS; Alistair Lees BVetMed MRCVS; Pippa Smith BSc BVSc MRCVS; Laura Freeman MA Vet MB MRCVS - at the Kingston Veterinary Group on 01935 813288.
