Understanding Laminitis: Causes, Stages, and Care
Laminitis is an acutely painful and disabling condition that occurs where the lamellae (the delicate folds of tissue that attach the pedal bone to the inside of the hoof wall) become inflamed and may eventually tear apart. The result is partial or total destruction of the strong bond that supports the horses body weight by anchoring the inner wall of the hoof to the pedal bone (the furthest extent of the leg).
Diagram of Normal Foot vs Chronic Laminitic Foot. Courtesy of Southwest Equine Veterinary Group.
WHY DO HORSES GET LAMINITIS? Excess body weight and altered weight bearing, and nutritional, hormonal, infections and mechanical factors are linked to the occurence of laminitis.
Excess body weight in humans increases the risk of diabetes and in horses of equine metabolic syndrome (EMS), which are almost identical and due to difficulties in managing blood glucose and insulin levels. Diets high in starch and sugar also lead to unnatural and dangerous blood glucose and insulin levels. Hormone changes associated with age (PPID or Cushings) and with pregnancy also increase the risk of laminitis. Mares become insulin-dysregulated anytime between 150 and 270 days of pregnancy and the risk of laminitis is increased in the last 4 months of pregnancy.
STAGES AND SIGNS OF LAMINITIS: There are four stages: developmental, acute, subacute and chronic – also called ‘founder’. Acute laminitis can persist, progress to the subacute or to the chronic form or resolve completely. Other than the chronic stage, no individual sign is present in every case of laminitis.
DEVELOPMENTAL STAGE: Laminitis often accompanies diarrhoea, foaling, metritis, pneumonia, colitis and tying-up. Anticipating risks allows prevention and early intervention. During this stage, the union between the hoof wall and pedal bone is being disrupted by microscopic changes in the blood flow and injury to cells.
ACUTE STAGE (lasts up to a week): onset of pain in both front feet, hind feet or all 4 feet, bounding digital pulse and heat in the hoof wall. Pain may only show as increased time lying down, reluctance to walk, lame or short, stilted gait at walk, difficulty turning, shifting weight, reluctance to lift the leg and pain on sole pressure. Importantly, the stance of ‘front feet in front of the body’ taken to represent the classic ‘laminitis stance’, occurs in less than 50% of affected horses.
SUB-ACUTE: The period of time beyond 72 hours after the onset of clinical signs during which the pedal (also called the coffin) bone remains undisplaced in relation to the hoof capsule.
CHRONIC: recurrent episodes, complete failure of the union between the hoof wall and the pedal bone, detachment of the hoof wall , dislocation of the pedal bone; coronary band swelling and depression, divergent growth rings, change in hoof wall angle, flat/convex sole, widened white line and recurrent abcesses.
CARING FOR AND SUPPORTING A HORSE WITH LAMINITIS: It is imperative to institute therapy during the developmental stage if possible or at the first sign of foot pain, as the window of opportunity for prevention is extremely small.
BEDDING, TRIMMING AND SOLE SUPPORT It is essential to ensure the foot is appropriately trimmed as a long toe and low heels increase the forces that result in rotation. A bedding of deep sand will support the foot, as will packing the foot with a rubberised compound (plasticine etc.) that moulds to the shape of the foot and provides even pressure across the entire sole and frog. Your veterinarian and farrier can work together to provide care, advice and guidance. Anti-inflammatory selection should be made in conjunction with your veterinarian as no two cases of laminitis are the same. The horse should not be forced to move, instead encouraged to lie down to prevent overloading of the inflamed and fragile laminae. Providing cushioning for the damaged sensitive sole may require a shoe, glue-on pad, pour-in support or a hoof-boot – depending on the case, the shape of the sole (concave or flat) and the stage of laminitis. No boot fits every horse perfectly and daily monitoring for rubbing is essential.
DIGITAL HYPOTHERMIA (immersing the legs in an ice slurry) can prevent the development and progression of laminitis. Cold has profound anti-inflammatory effects, pain relief (analgesia) and slows tissue metabolism, enhancing cell survival and allowing healing to begin.
DO YOU HAVE A HORSE THAT SUFFERS FROM LAMINITIS? A cornerstone in preventing and managing laminitis in all horses, is diet. Feeding a low sugar AND low starch, unprocessed feed ie not extruded or micronized, is the key! Equally critical are the nutrients needed to heal the torn and inflamed laminae that separate from the hoof wall and release the pedal bone to sink and rotate. Jenquine all-4-feet® is low in starch and sugar (NSC) and provides amino acids, biotin, anti-oxidants, vitamins and minerals essential for healing.
Dr Jennifer Stewart BVSc BSc PhD
CEO Jenquine, Equine Veterinarian and Consultant Nutritionist
