Nutritional management of laminitis
Professor Jo-Anne Murray
PhD, MSc, PgDip, BSc (Hons), BHSII, RNutr, PFHEA University of Glasgow Veterinary School
What is laminitis?
Laminitis is a systemic condition that manifests in the foot.
It is a condition that affects the laminae in the hoof. These laminae are “velcro-like” sensitive structures that connect the pedal bone to the hoof wall. Laminitis is the inflammation of these laminae, which become weakened, and start to breakdown – allowing the pedal bone to separate from the hoof wall and rotate towards the sole. Laminitis can be an extremely painful and debilitating condition that has major economic and welfare implications. It has the highest death rate of any orthopaedic condition and is the second largest killer of horses in the UK next to colic. It is also extremely common; in a recent survey involving 113,000 horses in the UK a prevalence of 7.1% was noted.
Symptoms of laminitis
The symptoms of laminitis can range in severity from mild lameness or shortening of stride (often described as a pottery stride) to unwillingness to walk and shifting weight from foot to foot accompanied by a strong digital pulse and slightly increased heart and respiration rate to total refusal to move, lying down a lot with heart rate over 80 bpm and respiration rate over 60 breaths/min. Changes in stance are often seen, where the horse is leaning back on to its hind feet to try and relieve the pressure on its front feet. But the extent of this depends on the amount of damage and which feet are affected, as any or all feet can be affected.
Causes of laminitis
Laminitis is best described as a syndrome rather than a single disease as there are a number of different causes. This article is focussing on the nutrition-related causes of laminitis, which we will look at under three broad categories: carbohydrate (CHO) overload, IR and Obesity. However, it is important to say that whilst nutrition-related laminitis can occur as a result of one of these issues, it is more often than not that these areas are linked, and that laminitis may occur as a result of some or all of these contributing factors.
Carbohydrate overload and laminitis
Nutrition has been liked to laminitis for a long time, in fact around 350 BC Aristotle used the term ‘barley disease’ to describe the development of laminitis after the consumption of excessive amounts of cereal grain (CHO overload). With CHO overload, some non-structural CHO (NSC) are undigested in the small intestine and pass through to the large intestine (LI) where it can cause a disturbance in gut health. Since the 1970s carbohydrate (CHO) overload has been one of the most researched aspects of laminitis. However, whilst ‘high-starch’ intakes from grain can cause laminitis, many studies have revealed that many cases of laminitis develop in horses and ponies grazing on pasture, which gave rise to the term pasture-associated