Laminitis is an inflammation of the laminae (or lamellae) part of the horse’s hoof. It can be extremely painful and debilitating to horses and in extreme cases can lead to the coffin (or pedal) bone protruding through the sole of the hoof. When this happens it can make it impossible for the horse to stand, sadly often requiring the horse to be euthanized which is why it’s so important to ideally prevent laminitis but if that’s not possible then treat it immediately. The good news though is that if treated promptly its generally not only survivable but a lot of horses will make a full recovery.
What causes laminitis?
There’s a lot of different things that can lead to laminitis but as a rule of these fit into one of three main causes.
- Inflammatory – A secondary response resulting from some form of inflammation because, in an attempt to deal with the original problem, the horse’s enzymes start to break down the laminae. Severe diarrhoea, infection as well as eating something toxic (you may find this article I wrote on what not to feed your horse will help with this) can all indirectly cause laminitis. To prevent this secondary response you can pack your horse’s feet in ice. This will help to keep them cool but you should also seek advice from your vet as to how to keep his lower legs cool too. This is extremely important because if you leave it expecting it to clear up then it’ll likely be too late to prevent any damage.
- Metabolic – Metabolic laminitis is caused by an insulin resistance which can lead to a higher than normal amount of insulin. Healthy horses will be able to, within a couple of hours, regulate their levels of insulin (which is what helps your horse regulate its blood sugar levels), but horses with a resistance aren’t able to do this so will tend to have increased levels of insulin can cause the laminae to grow, leading to laminitis. There can be a number of reasons why a horse can be insulin resistant, but obese horses will also have the same problem. An abnormal metabolism can result from many things such as:
- Cushing’s – Cushing’s or pituitary pars intermedia dysfunction (PPID) is disease where the horse is no longer able to regulate the secretion of the pituitary gland hormone. This can have a number of symptoms such as long fur, loss of muscle, pot belly and excessive drinking but it can also effect the horse’s metabolism which can in turn lead to laminitis.
- EMS – Like Cushing’s, EMS (or equine metabolic syndrome to give it its proper name) is a condition where the horse isn’t able to control its carbohydrate metabolism. It’s more common in certain breeds such as mountain and moorland ponies, Morgans, Paso Finos, Saddlebreds and Warmblood and while it’s not unheard of in Quarter Horses, Tennessee Walkers and Standardbreds it’s far less common. While EMS is not related to obesity its effects are far worse in overweight horses.
- Obesity – As with humans and diabetes, horses that are unhealthily overweight are far more like to be insulin resistant.
- Spring grazing – During the spring months pastures tend to be richer in sugar which can spike to insulin levels.
- Overload – This is where a horse, for whatever reason, isn’t able to put weight on one of their legs. The opposite leg will become overloaded which can then lead to laminitis in the load bearing leg. American champion racehorse, Barbaro, is the most famous case of this. He fractured his hind leg which was successfully treated but because the opposite leg was overloaded he suffered laminitis and sadly had to be euthanized. Thankfully though overload laminitis isn’t very common.
How to spot laminitis?
Noticing laminitis early is of paramount importance if it’s to be treated successfully. That said it can be difficult to diagnose it in the very early stages, often requiring X-rays to confirm a diagnosis. If you notice that your horse has any of the following symptoms you should contact the vet straightaway. As with humans the same symptom can point to multiple conditions but when your horse is displaying more than one symptom it’s definitely time to call the vet.
- Higher heart rate – It’s a little known fact that horses will have a slightly higher heart rate a few days before other symptoms of laminitis start to show. A normal heart rate is between 30 and 40 beats a minute at rest, but an increase of just six beats can be a good sign of the onset of laminitis.
- Faster pulse – While a faster heart rate can be a symptom of many things laminitis is one of them. You should be able to faintly feel your horse’s pulse just behind his fetlock but if the pulse feels fast and stronger in all four legs it could be an indication of laminitis. A strong, fast pulse in just one leg could mean your horse is suffering for lameness or other foot problem.
- Hot hoof or hooves – If a horse suffers any trauma to the tissue of the hoof (or any other tissue for that matter) then the first sign of this will be that the area is hot to touch. If you’ve just been for a long gallop then of course the hooves will be hot but if the heat is still there hours later this is cause for concern.
- Strange rings or shapes on hoof – Like our fingernails a healthy hoof will be smooth and have steady growth. With laminitis this isn’t the case, the hoof will often be rough with wide uneven rings. A healthy hoof will also grow faster at the front while a hoof with laminitis will grow quicker at the back.
- Stretched or bleeding laminae – A stretched laminae will separate from the wall of the hoof with a gap between the sole and the wall appearing. This is probably the most common symptom of laminitis, but in some cases the laminae will also hemorrhage which is noticeable by blood in and around the gap.
- Shorter stride – Before a horse starts to limp he’ll often shorten his stride slightly, especially on harder ground. This is a classic sign on laminitis and is because of the pain the horse feels from the laminae
Stages of laminitis
Around 35% of all horses and 80% of ponies are thought to be at risk of laminitis and while it’s the second most common cause of horse deaths (after colic) not all cases of laminitis are that severe and if treated quickly won’t lead to chronic laminitis. The outlook for a horse suffering with laminitis will be determined by the stage of the condition the horse is in, obviously the sooner it’s treated the better the prognosis will be.
- Developmental – A relatively short period of between 1 to 2 days which lasts from when the horse was first ‘exposed’ to the cause of laminitis to when the first clinical signs show.
- Acute – After the first clinical signs have shown themselves the laminitis will then move into the acute stage. This lasts for around 72 hours and how he reacts to treatment will determine if it’ll develop into chronic laminitis or start to improve and move into the subacute stage.
- Subacute – If the laminae only has minimal damage your horse will start to make a full recovery and the coffin bone never suffers an injury.
- Chronic – If your horse doesn’t respond well to treatment in the acute stage, or if the damage to the laminae is severe then it’s likely the coffin bone will become displaced and the laminitis will move into the chronic stage. This is the most serious stage because it’s when the dermal and epidermal laminae can separate. It can still be treated but most horses won’t make a full recovery and will suffer laminitis flare ups in the future.
Page 2 – Prevention and treatment