Winter finally seems to be on the retreat and Spring is in full bloom. Poached, muddy fields have dried out and are now rapidly greening up in a miraculous regeneration that seemed impossible a matter of days ago. Whilst the arrival of a lush carpet of "Dr Green" is very welcome and heralds the season of plenty for many horse owners it can mean just the opposite for those whose horses suffer from laminitis.
What is laminitis?
Laminitis is an extremely painful and debilitating condition in which the blood flow to the sensitive laminae beneath the hoof wall is compromised. Inflammation and swelling of the tissues within the hoof occurs depriving the laminae of oxygen and nutrients carried in the blood. Without urgent and prompt treatment, cell damage occurs and the laminae begin to die.
One function of the laminae is to provide support to the pedal bone which in turn bears the weight of the horse. When laminitis becomes severe the pedal bone can sink and rotate and in severe cases may be seen to protrude from the sole. This is usually irreversible and the affected horse must be put to sleep on humane grounds.
The condition is more usually seen in the front feet although it can occur in all four. Both horses and ponies can be affected.
What causes laminitis?
There are a number of factors which can predispose a horse to getting laminitis. Overweight animals are particularly susceptible.
An excessive amount of soluble carbohydrates in the diet overloads the horse's digestive system. Undigested sugar and starch are pushed through to the hindgut where they are broken down by bacteria. This causes acidic conditions which kill fibre digesting bacteria. As the bacteria die they break down and release toxins into the gut. These toxins pass through the gut wall and into the bloodstream triggering a physiological response in the horse which disrupts blood flow. Such disruption, if it affects the horse's feet, can cause laminitis.
Stress is a major trigger for laminitis. Frequent travelling, environmental changes and mares which have recently foaled are particularly at risk.
Where a horse has suffered a severe bacterial infection, colic, or complications following foaling resulting in toxaemia (blood poisoning), laminitis can be a side effect.
Obese horses are particularly at risk from laminitis. Just as in people, horses ingesting more calories than they burn off will quickly become overweight, especially during the Spring and Autumn when the grass is growing and is high in sugars. Native breeds are particularly susceptible if their winter feed ration is not sufficiently reduced or their grazing time managed effectively.
Another common cause of laminitis is concussion. Horses in prolonged fast work on hard surfaces, especially those with poor hooves, can suffer bouts of laminitis as the laminae are traumatised.
Laminitis can be a side effect of Cushing's disease, an abnormality of the pituitary gland usually affecting older ponies.
How to recognise laminitis
Acute laminitis presents with a very rapid onset and severe symptoms.
An affected horse will be markedly lame and reluctant to move especially on a hard surface. A strong digital pulse will be present in the foot. The horse will seek to relieve the painful pressure on its front feet and may try to take its weight backward onto its hind feet or may lie down and be unwilling to get up again. There will be extreme pain in front of the point of the frog so the horse may try to place its heels down first, rather than its toes as it walks. Mild colic-type symptoms may also be present.
In chronic laminitis, ongoing symptoms are displayed as a result of relapses from previous bouts of the condition. Growth rings will appear around the hoof wall and the heel will very often grow faster than the toe. The white line in the hoof wall will appear widened. The horse might also have a notably large, cresty neck.
Immediate veterinary attention is essential. The affected horse should be placed in a small pen or stable with a deep bed of shavings, shredded paper or some other product that will mould into the hoof and around the frog to provide support. The horse should have a companion nearby and his new environment should be as stress-free as possible. Any feed should be removed until veterinary direction is given as to a suitable diet.
The hooves should not be cold hosed as although this may initially provide relief for the horse, prolonged cold will only make things worse.
X-rays may be advised by the vet to establish whether rotation of the pedal bone has occurred and remedial farriery will probably also be required to manage the condition and hopefully promote recovery.
Always feed in accordance with your horse's work load and breed/type, making adjustments as necessary for grass growth, quality of forage etc. Most feed companies offer a free advisory service to owners to help them formulate a correct nutritional program for their horses.
Horses should never be starved as this can lead to serious health issues. Stick to high fibre, low sugar products and steer clear of cereal mixes and anything containing molasses, including treats and licks. A probiotic supplement can be added to feed to help maintain a healthy hindgut.
There are less harmful fructans, (soluble carbohydrates), in grass at night so restricting grazing in line with this can be helpful. Ryegrasses and clover have a higher sugar content than more traditional grasses and herbs so where possible and manage sward accordingly.
Vulnerable animals should be checked daily for early indicators of laminitis such as slight lameness or pottery gait; a hard crest, a more pronounced or changed digital pulse.
Detected early, laminitis can often be successfully managed. Left too long without treatment or not spotted quickly enough, the condition can cause permanent damage and sometimes euthanasia is the only kind and humane option.
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