Contrary to the popular belief, laminitis in horses occurs all year-round, not just in the spring. It is an emergency that needs prompt action whenever it is suspected, so find out how to recognise it and what to do if your horse is showing signs
What is laminitis in horses?
Laminitis in horses is an inflammatory condition of the laminae within the feet – the tissues that attach the pedal bone (the bone in the centre of each foot) to the hoof wall inside the hoof capsule. Although many people mistakenly think laminitis is only suffered by overweight ponies, horses of all types, age and size can develop laminitis for many reasons.
The condition occurs when the sensitive laminae within each foot become inflamed, but they are unable to swell since they are restricted by the solid external structure of the hoof. This leads to the horse feeling extreme pain and adopting the classic leaning back on the heels posture in an attempt to relieve the pressure from the front of the hoof. In the most severe cases the horses will lie down as their feet are too painful to bear weight.
An acute new episode or flare up of laminitis is a veterinary emergency and an equine vet should be called to assess any horse with suspected laminitis as a matter of urgency. Some horses and ponies have long standing chronic laminitis, which may not be an immediate emergency, but still needs expert care and attention. According to the RVC1 more than 7% of equine deaths are linked to laminitis, with many cases being put down on welfare grounds.
Laminitis can develop very rapidly. It can result in the pedal bone sinking or rotating within the hoof and in extreme cases the pedal bone can drop so far that it penetrates through the sole of the hoof. If the pedal bone completely detaches from the hoof wall then the horse has ‘foundered’ and euthanasia may be the only option.
Laminitis: Signs | Diagnosis | Causes | Treatment | Prevention
Early signs of laminitis
Early signs of laminitis include the horse taking a shorter than normal stride and being reluctant to walk on hard or stony going, choosing grass or softer ground when possible. The horse may appear more lame on hard ground and turns, and may shift its weight between feet when standing still.
Other signs of laminitis in horses
Lameness is typically seen in all four legs, although the forelegs may appear more badly affected. Signs of laminitis to look out for include:
- An increased digital pulse at the back of the pastern/fetlock
- The hooves may feel warm to the touch, although this alone is not a reliable indicator
- Pain will be shown with use of hoof testers, especially around the point of frog on the foot
- The horse stands leaning back onto its heels – the classic laminitic stance
- The horse may lie down, and be unwilling to get to its feet
When do you see laminitis rings on the hoof?
Clear rings on the hoof wall can be a sign of a horse with chronic (i.e. long standing) laminitis. A horse that has suffered repeat bouts of the condition is likely to have misshapen feet with horizontal rings or lines on the hoof wall, which are wider at the heel than at the toe. The sole of the hoof may be flat or convex, with a wider than usual white line.
How is laminitis diagnosed by a vet?
A vet should be consulted if laminitis is suspected and will usually diagnose the condition based on the clinical signs. X-ray images are useful to confirm whether the pedal bone has sunk or rotated, which will help as a guide to prognosis and inform the farrier fitting shoes. Blood tests can be very useful to help identify if any underlying endocrine disease is responsible.
What causes laminitis?
In general, ponies tend to be more susceptible than horses to laminitis, although the condition can affect horses of all breeds, sizes and ages. Risk factors associated with the disease include a flush of fresh grass at any time of year, grazing when the grass is under stress (such as after frost or severe overgrazing), and horses that are overweight.
Underlying conditions that can lead to laminitis include equine Cushing’s disease (also known as pituitary pars intermedia dysfunction or PPID) and equine metabolic syndrome (EMS). The hormone insulin appears to be significant in laminitis associated with endocrine disorders.
A 2021 study2 conducted by Scotland’s Rural College in collaboration with the Waltham Petcare Science Institute found that steps taken to protect public health during the Covid-19 pandemic – including reduced exercise, turning horses away, and limiting yard visits – had the potential to compromise the welfare of overweight equines, increasing the risk of laminitis.
David Rendle, chair of the British Equine Veterinary Association’s health and medicines committee, said: “The study provides testimony that many horses spent additional time at grazing as a result of Covid health guidelines. Vets have been concerned throughout the pandemic that increased turnout during periods of good weather could tip laminitis-prone animals over the edge into clinical laminitis. The fundamental issue is the unacceptably high proportion of equines with obesity and associated metabolic disease.”
Research3 led by Garance Christen at the Swiss Institute of Equine Medicine, University of Bern, published in 2020, found that horses aged over 25 may suffer from chronic laminitis without displaying any outward signs or suffering from contributory health conditions. Almost half of the total sample of 51 clinically sound horses from different age groups (15-32 years) showed signs of rotation on X-ray, although none of them showed signs of acute lameness or PPID. Of these, horses aged over 25 were found to be three times more likely to have pedal bone rotation than horses in the younger age category.
The study’s authors said: “We think that radiographic changes are related to early or pre-clinical PPID in this cohort of horses because this remains the best explanation for the higher incidence of laminitis in the old age group.”
Other causes of laminitis
Laminitis can also be caused by a retained placenta after foaling, following on from another illness, limb concussion caused by excessive work on hard ground, or overload of a limb due to a severe injury of the opposing leg. In these instances, if the primary condition is effectively treated, the laminitis risk will subside.
In diseases associated with inflammation (such as certain types of colic, diarrhoea, retained placenta and severe pneumonia), the inflammation throughout the body triggers inflammation of the laminae, although why this happens remains unclear.
In mechanical overload laminitis, such as when a fracture or infected joint causes the other leg to bear all of the horse’s weight, it’s thought the excessive and continuous weight bearing may negatively affect the blood supply to the laminae.
Cases linked to concussion can occur during the summer in susceptible animals when a heatwave bakes the ground, with ponies in active service during the school holidays, as well as show horses and racing thoroughbreds, at a higher risk.
A vet should be consulted regarding any suspected case of acute laminitis as soon as possible. They may prescribe non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone or flunixin and potentially other painkillers to help manage the horse’s discomfort.
Foot support and complete rest to limit movement of the pedal bone is important and will help to reduce the extreme levels of discomfort. The horse should be placed on box rest on a deep bed of shavings or other similar bedding right up to the stable door. Special supports can be attached to the horse’s hooves by your vet or farrier to give additional support.
Acepromazine (ACP) has been frequently used to increase the blood supply to the feet, but it’s beneficial effect may be more due to its sedative properties, which will encourage the horse to stand still or lie down.
In cases of laminitis associated with inflammation, the use of ice to cool the feet may be beneficial, especially in the very early stages of the disease. Research comparing seven different ways of cooling the hoof4 found immersion of the foot and at least the pastern region of the leg in ice and water achieved the lowest hoof wall surface temperature for a sustained period, along with use of a prototype perfused cuff device with a dry interface. In summary, when apply cold therapy, the cooling should cover the whole hoof as well as the lower part of the leg for the greatest effect.
If the laminitis is the result of an underlying condition, such as an endocrine disorder, that should be treated accordingly. Discuss this with your vet, depending on the results of blood tests. If a horse or pony has insulin regulation problems caused by EMS or PPID, or both, he will certainly be at increased risk of developing laminitis and will require careful management. By diagnosing these underlying problems the vet can guide the owner more clearly and manage the case more effectively.
A new treatment for laminitis
Ertugliflozin, an SGL2 inhibitor used to help lower blood glucose levels in humans, has been found to successfully lower insulin levels in horses, and is being successfully used in the treatment of laminitis and equine metabolic syndrome (EMS). Veterinary expert David Rendle, who has been involved in the early research5, said the drug can bring insulin levels down “remarkably quickly”, adding: “We have found in cases of laminitis the horse’s level of comfort increases very quickly. Everything is pointing toward SGL2s being an effective way of reducing the suffering associated with laminitis.” Although the drug does not have marketing authorisation for use in horses, but it can be prescribed by a vet in the UK.
Feed for horses with laminitis
Diet is very important during bouts of laminitis. Clean fresh water should always be available while the horse should be fed poor quality hay, rather than grass. The hay should be soaked for at least an hour to reduce soluble carbohydrate levels. Fibre-rich feeds such as unmollassed sugar beet and low-sugar chaffs can also form part of the diet.
Horses that are overweight should not be starved in an attempt to shift excessive condition as doing so risks triggering hyperlipaemia, a disorder of fat metabolism.
All horses need to receive a balanced diet of vitamins and minerals, so discuss the best way to supply this with your vet. Once the acute stage of the condition is over, hoof supplements can be used to promote healthy hoof growth, while other supplements are formulated to help support healthy horses on restricted grazing.
How to prevent laminitis in horses?
While it is not only overweight ponies that get laminitis, the weight of all equines should be carefully managed to reduce the associated risk. Horses of all types need to go into the spring in lean condition (where you can easily feel and just start to see their ribs) to avoid the risk of obesity as the levels of nutrition in grazing improve. Winter is a great opportunity to achieve weight loss in overweight equines by keeping them unrugged and not increasing hard feed, unless the horse drops clearly below a healthy bodyweight. Grazing muzzles can be used all year round to help control weight gain.
All horses hooves should be attended to by a qualified farrier every four to six weeks, whether they are shod or not, to maintain correct hoof balance and health. Appropriate shoeing can make a huge difference to the chronic laminitic by supporting the structures in the foot properly. There are many options of useful shoes designed to help laminitis cases including mouldable thermoplastic shoes and clogs amongst others.
The farrier who sees the case every few weeks is also in an excellent position to guide the horse owner, who sees their animal daily and therefore may not notice changes, especially in weight.
Avoid excessive trotting/cantering on hard ground, including roads, to reduce the concussion on the horse’s limbs and feet.
In broodmares after foaling, check that the whole placenta has been expelled. If you are unsure if this is the case, contact your vet urgently.
If your horse is recovering from a severe injury to one leg, discuss with your vet the best way to provide additional support to the opposing limb.
Above all be aware that we now know that there is much more to laminitis than simply avoiding lush grass. Underlying metabolic problems, proper regular attention to the feet and good general health care are all important.
What is the worst time of year for laminitis?
While laminitis can occur at any time of year, it is often seen in spring when the grass grows at a fast rate. This is typically the case in overweight equines, who are suffering with associated metabolic disease.
Should you walk a horse with laminitis?
No, a horse with laminitis should not be walked. Any horse with laminitis should be kept on box rest with a deep soft bed, such as shavings, to limit the risk of movement of the pedal bone while the inflammation of the laminae is ongoing.
How long on box rest for laminitis?
Every case of laminitis is different, but a horse is likely to need to be on box rest for at least a month after the initial signs of pain pass, even for a mild case of laminitis. More serious cases are likely to have to remain on box rest for a number of months while treatment is ongoing.
- Royal Veterinary College’s laminitis fact file pub. undated
- COVID-19 impacts equine welfare: Policy implications for laminitis and obesity pub. May 2021
- Age over 25 years, but not plasma adrenocorticotropic hormone concentration above the seasonally adjusted reference range is predictive for radiographically assessed changes of chronic laminitis in elderly horses pub. December 2020
- A comparison of seven methods for continuous therapeutic cooling of the equine digit pub. January 2016
- Preliminary observations on the use of ertugliflozin in the management of hyperinsulinaemia and laminitis in 51 horses: A case series pub. November 2022
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