As Laminitis season is almost upon us, now is a good time to have a read of our guide on Laminitis Symptoms & Preventative Measures, written by Amy Horne. Amy’s interest in Equine Laminitis stems from her personal experience with her own horse. She achieved a first class BSc (Hons) Animal Biology degree where she specialised in the aetiology and pathogenesis of Equine laminitis. She has been published in the Veterinary Times on the subject and now aims to use her expertise to help others.
What Is Laminitis?
Laminitis is an inflammatory disease of the hoof affecting the laminae. Laminae are a type of keratinized epidermal tissue which suspend the pedal bone in the hoof capsule and connect to the inner wall of the hoof.
Laminitis causes pain and discomfort due to damage to the laminae weakening the connections of the hoof which hold the pedal bone in place. Laminitis can cause rotation from the deep digital tendon and sinking of the pedal bone. This may cause the pedal bone to come through the sole, hence the prognosis is poor if this occurs.
Why Is Laminitis Such A Serious Condition?
Reoccurring attacks of laminitis pose a real threat to the health and wellbeing of the horse. Despite a reduction in pain and moderate rehabilitation, the affected hooves will never fully recover, especially if the pedal bone has moved. Laminitis causes weakening of the lamina which means the horse will be more sensitive to further episodes, as the connections of the hoof become scarred.
Furthermore, the pedal bone is unable to reposition to its original anatomical location and therefore further downwards displacement can lead to penetration through the sole.
There are numerous causes of laminitis, with the main ones being Cushing’s (Pituitary Pars Intermedia Dysfunction), Equine metabolic syndrome (EMS) and carbohydrate overload induced laminitis, caused from eating foodstuffs which are too high in non-structural carbohydrates, i.e. sugar!
What Are The Causes Of Laminitis?
Pituitary Pars Intermedia Dysfunction
Cushing’s is a disease of the pituitary gland where abnormalities form and a benign tumour develops, causing a hormonal imbalance. Cushing’s causes high levels of cortisol, in the form of ACTH, to be released, which effects insulin and its ability to control the blood sugar levels. Unfortunately, this results in heightened levels of glucose, which is toxic to the tissue of the laminae and causes the cells to become misshapen and collapse, resulting in laminitis.
Equine Metabolic Syndrome
EMS is a disease similar to Cushing’s that affects the insulin levels and the body’s ability to effectively deal with glucose. EMS is commonly seen in native breeds which have the ‘thrifty gene’. This is understood to aid survival in the wild by storing energy, particularly in the crest. With modern management, these breeds are very susceptible to obesity and this in turn can result in laminitis; again due to the high levels of glucose damaging the laminae. However with weight loss, insulin sensitivity does increase and therefore the risk of laminitis is also lowered.
Carbohydrate overload occurs when horses eat too much of the non-structural carbohydrate, fructan, often from eating too much lush grass. This causes fermentation to increase, resulting in a build-up of lactic acid in the hind gut. The levels of harmful bacteria rise as a result and some pass through the lining of the hindgut into the circulatory system causing the immune system to fight off bacteria using enzymes. However the laminae is wrongly targeted and laminitis occurs.
How To Spot The Signs And Symptoms Of Laminitis
One of the first indications of laminitis is an increased digital pulse (Figure 1). This represents inflammation and a raised temperature of the hoof. The hooves may be warm to the touch, especially the front. In a horse with laminitis it can feel as if the digital pulse is throbbing.
However every horse is different and therefore it is important to know what is normal for your horse.
Laminitis can alter the stance, as the horse will try and place weight on the hind feet to relive some pressure off the front; showing the classic laminitic stance.
The horse may be unwilling or hesitant to move and the gait may appear stilted. Furthermore, the horse may appear fidgety and transfer the weight from hoof to hoof; this is a sign of discomfort and therefore it is important that the horse is not forced to move.
Although both obesity and having a cresty neck are not signs of laminitis, they are an indication that your horse is at a high risk.
Figure 1. To check the digital pulse, place your middle and ring finger on the inside of the leg and apply slight pressure to the artery (indicated by the arrow). Reajust until you find the pulse. If you are unable to find the pulse, it is unlikely your horse has come down with laminitis. If the pulse is bounding (strong as if it’s throbbing) this is a sign of inflamation and therfore laminitis, but do check all four legs.
What To Do If My Horse Gets Laminitis
If your horse becomes affected by laminitis, first ring your vet to come out as an emergency. The vet will assess the severity of laminitis and gauge the next steps to take in order to relive discomfort and limit damage to the hooves. This may involve giving pain relief and referring to a remedial farrier. The sole of the hooves will require mechanical support to ease pain, limit damage to the laminea and distribute the weight away from the pedal bone.
If the horse is willing and able to walk without too much discomfort, remove from the paddock and place in the stable. If the paddock is a distance from the stable, transporting the horse is advisable to prevent causing more damage. A deep bed of shavings, approximately 6 inches will maximise comfort and help to support the hooves; however ensure banks are put in place to reduce the risk of getting cast. Do not starve, but soak the hay in water to reduce the sugar and starch content.
Ensure that the horse is relaxed as possible and can see other horses, as stress can exacerbate laminitis. Soaking the affected hooves in ice water for approximately 30 minutes will help to reduce the pain and swelling regardless of the initial cause. Do not give any hard feed or medication before seeing the vet.
Laminitis Management and Prevention
- During the warmer months, limit grazing to night time or early mornings, as the sugar content of the grass is heightened during day light hours, particularly on warm sunny days.
- In contrast, avoid grazing when the temperature is 5˚C and below, as fructan levels increase.
- To prevent obesity and to reduce the sugar content of hay, soak in fresh water for 3-12 hours (sugar levels are reduced after 30 minutes of soaking, however for a significant reduction a minimum of 3 hours is required). As soaking hay also removes necessary nutrients, it is important to feed a balancer to ensure the dietary requirements are met.
- To limit grazing and prevent obesity, use electric fencing to divide large areas into smaller sections.
- Over grazing can stress the grass and cause sugar levels to increase. Therefore move the fencing regularly to prevent this.
- Maintaining a healthy and slim body condition score is vital in the prevention of EMS and laminitis. However, ensure that the horse gets a minimum of 1.5% of their body weight per day of forage to prevent complications.
- Exercise increases the sensitivity to insulin and therefore blood glucose levels are lowered. However, only exercise if you have the go ahead from your vet.
- Using a weight tape, assess the weight and body condition score on a weekly basis and alter the diet accordingly (sudden weight gain significantly increases the likelihood of laminitis).
- It is important to note that laminitis can strike throughout the year to both ponies and horses and therefore vigilance is essential!