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Sugar causes laminitis

‘The sweet seducer’
by: Jessica Bunjes

The nightmare of many horse owners in the turning out season is laminitis. The fear of too much protein in the feed determines the behaviour a great deal. But protein is not the cause of laminitis at all. This is the result of the research carried out by the Australian professor Christopher Pollitt (University of Queensland):”sugar is the main cause of laminitis”.

“The assumed relationship between laminitis and protein is easy to explain as the disease appears most of the time in the spring when the new grass grows and the grass contains a lot of protein”, states veterinary surgeon Leendert Jan Hofland, member of the Pavo GroomingTeam. This is a team of experts who provide free advice to horse owners on www.pavo.net. “According to the latest findings, the main cause of laminitis during the turning out season is a complex sugar, called Fructan, which is produced by grass”, states Vincent Hinnen, who is also a member of the Pavo GroomingTeam. He refers to the investigations of the Australian professor Christopher Pollitt.

Fructan causes laminitis

The complex sugar Fructan, a polysaccharide, is produced in grass through the influence of sunlight during the photosynthesis (the metabolism of grass). It is a building stone and is used as a temporary store of energy, produced by the photosynthesis and not directly used for the growth of the grass. The amount of energy produced and used depends on many factors. Among them, the intensity of the sunlight, the temperature and the type of grass: A lot of sunlight and warmth means strong growth, resulting in low levels of Fructan. Sunlight and cold cause a high level of photosynthesis and little growth, resulting in a high proportion (90%) of the energy stored as Fructan and carbohydrates (starch).

The horse as diabetic

The Fructan content in grass changes a lot: When cold and sunny the content is 200 times higher as when warm, overcast or rainy days. Vincent Hinnen warns: “You can expect the highest levels of Fructan when sunny and freezing, when the temperature at night is below 5 degrees Celsius, when the fields have not been fertilised or when it is extremely dry. In contrast, a lot of protein intake during the turn out season is no problem”. Veterinary surgeon Drs. Hofland states: ”The horse can deal with a temporarily too high intake of protein. Especially when the horse can get used to that gradually”.

A returning sugar-high is bad for the horse as it is for human diabetics. “The blood sugar level increases sharply when the horse eats a lot of sugar rich grass in spring. The body of the horse can’t cope with that”, states Vincent Hinnen. “Also the gut flora in the large intestines can’t process such high concentrations of Fructan”. Vet Hofland adds: “Hard feeds containing a lot of carbohydrates and sugar, or feeds with a lot of barley and maze, can’t be digested properly in the small intestines. As a result they are digested in the large intestines”. Vincent Hinnen continues: “ The process is as follows: the hardly or undigested food mass ends up in the large intestines, which are populated by bacteria who can digest roughage cells and carbohydrates.

Because of the surplus of carbohydrates, the relevant bacteria multiply explosively and produce lactic acid as a by-product. This lactic acid reduces the pH value in the large intestines from 7 (neutral) to a more acidic value like 6. This kills the bacteria, which digest the roughage cells and this dying produces poisons, called endotoxins. These damage the lining and walls of the guts and lactic acid gets into the bloodstream. That causes the whole organism to become acidic, including the hooves, resulting in the inflammation of the hoof lamina, which causes the irreversible and extremely painful relocation and rotation of the pedal bone. In other words: the horse or pony has laminitis”.

The right grass

“Fields sown with English rye grass is not ideal for horses, because this grass produces a lot of leaves and therefore, could produce a lot of Fructan. In areas where horses have always lived, the situation is different. In the wild, horses eat a different type of grass, their eating is spread over the whole day and there is less grass per square meter. In modern equestrian centres, the horses eat more in less time”, says Vincent Hinnen.

“Horse owners should sow types of grass with low Fructan levels”, he advices. The nutritional expert declares the idea that rich fields are more dangerous than topped fields as nonsense. The stems can store big amounts of Fructan. On the other hand, there is less grass in topped fields, so the horse will eat less grass, which reduces the chance of getting laminitis. His basic advice is: “In spring, limit the time the horses are turned out or reduce the size of their field or turn them out in a small paddock with little or no grass. In those cases, remember that you have to feed the horses hay with long stems. You also have to be extra careful with horses who have had laminitis before. They are ultra sensitive and hay can also contain Fructan.

Prevent laminitis

Roughage has to be the essential ingredient of a horse’s overall diet. The only way to play safe with hard feed, is to feed expanded cubes or roasted mixes (muesli’s). That way the treated carbohydrates can de digested properly. Vincent Hinnen adds: “horses who are prone to get laminitis are not allowed grains like barley or maze, because only 30% of their carbohydrates can be digested. If you insist on feeding grain, then use oats, as their carbohydrates are 80% digestible”.

His advice is, that after a cold night, you should only turn the horses out in the afternoon. Also, fertilise the fields early in the year with 10 to 15 cubic meter of composted manure. The manure contains phosphorus, potassium and nitrogen, which reduce the sugars. The most important reason to fertilise is to keep the grass growing. No growth means that the Fructan is not changed into energy and stays in the grass.