- Digestive system

A horse that rolls, kicks the ground and looks round at the flank… These symptoms, well known to riders, are closely watched for. It should be said that “ colic”, a word that gathers together every type of abdominal pain, is the dread of every horse owner, and for good reason : This disease is the biggest cause of mortality in the horse.

The horse, possessing a unique digestive system, is of particular risk from suffering from colic. The pain can be caused by an infection, or be related directly to the horse (his age, breed…), but also may be linked to his lifestyle. It is therefore possible to minimize the risk of your horse developing colic by controlling : for example, the way he is fed, watered and housed.
Colic refers to pains that can affect the stomach, the small intestine, the caecum or the colon. In the large majority of cases, colic symptoms are related to a digestive blockage. This blockage may be due to a material obstruction (a very fibrous food such as straw, wood shavings, sand, parasites) or strangulation of a section of the gut. Colic symptoms can also be related to a massive build up of gases in the caecum/large colon, following the ingestion of a too large quantity of fermentable sugars (starch and/or fructans). Ulcers affecting the stomach and/or small intestine can also be at the root of colic symptoms and can become chronic.

What should be done to reduce the risk of colic?

Colic affects different regions of the digestive system and is related to various causes, so is therefore of multifactorial origin. Thus housing, managing health and feeding can all play a role in preventing this digestive disorder:

      Reducing the time spent in the stable and increasing the time spent out at grass, lowers the risk of colic. Indeed horses turned out at least 3 times a week have less risk of colic than horses who do not get access to turnout during the week. This is even of greater importance to horses who crib-bite or windsuck as they are more subject to colic.
      Thus an environment which allows the horse to move around (walking stimulates the intestinal transit), and keeps him occupied, helps minimize the risks of colic.
      Offer ad-lib clean water at a temperate temperature. Dehydration is a major risk for the development of colic in the horse, due to the fact of the risk of obstructions due to dehydrated food. Horses without access to water at all times in their stable, field or paddock are more at risk of suffering from colic, more so if the horses are aged. Travelling is also a risk factor in the development of colic, in part due to insufficient watering, stress and/or heat.
      Thus the importance of offering the horse ad-lib access to clean water at a suitable temperature at all times.
      Put into place a serious worming routine and regular dental care. Horses who are not wormed, or who have been wormed recently because showing signs of massive parasite infestation (dull coat, pot belly, loss of condition…) have more risk of colic than horses whose management includes a serious parasite control programme. A large number of dead parasites (worms) suddenly dumped in the digestive system can notably cause particularly painful obstructions. Finally, dental health is of paramount importance to effective digestion, and horses suffering from dental problems are more at risk of colic.
      Therefore, it is important to worm with regularity (in collaboration with your vet) and to organise regular dental care.

    • FORAGE
      The horse’s diet is based on forage. Thus, each extra kg of hay given to the horses reduces 3 fold the risk of colic. In the same manner, a study undertaken at the Centre Hospitalier Universitaire Vétérinaire at Ghent (Belgium) demonstrated that 33% of horses that were admitted for colic received less than 1kg of hay per 100 kg live-weight per day against 0% for those horses admitted for non-intestinal related problems. Forage quality is also of importance, and horses eating poor hay have a higher risk of colic, the same applies to horses eating hay directly from the bale.
      We advise feeding a minimum of 1.5kg of hay per 100kg of live-weight per day. Hay must be of good quality and stored in such a way as to avoid pathogens developing.
      Feeding concentrate foods must be well thought out and fractioned into a maximum number of meals. Indeed, horses weighing 500kg and receiving more than 5kg of concentrate feed a day are 6 times more at risk of suffering from colic than those being fed less than 2.5kg a day. The ingestion of over-sized concentrate meals, can in effect, cause an obstruction, blocking the intestinal transit as well as undesirable fermentations in the caecum and/or colon if there is too much starch. The horse’s ability to digest starch in the small intestine is limited. Therefore, if the there is too great a quantity of starch, it will pass directly into the large intestine where it will be fermented by lactic bacteria. This causes acidification of the environment, which is harmful to the intestinal cells and intestinal microbiota. These fermentations also lead to a large amounts of gas being produced and is painful (tympanitic colic also known as bloat, wind colic or gastric tympany).
      We thus advice giving no more than 150g of starch and 400g of feed for every 100kg of live-weight per meal. Furthermore, small meals are better digested by the horse, disturbing less his metabolism and gastric health.
      In the case of a change of food, a progressive dietary transition is advised. Indeed, an abrupt change in the type of concentrate feed or forage being given leads to a rise in the risk of colic in the 14 day period following the feed change, and in particular within the first 7 days.
      We therefore advise spreading the dietary transition over about 10 days so the digestive system and the intestinal microbiota can progressively adapt to the new diet.

Re-feeding a horse following colic

    It is advocated to withdraw water and food during colic until the episode has finished. In the first few days following colic, feeding concentrate feeds is not recommended so as to limit production of gases in the large intestine. With the aim of rebalancing the intestinal microbiota, administering a pre-pro-postbiotic supplement, such as REVERDY FLORE is recommended.
    Rapidly after surgery, if the horse shows an absence of gastric reflux, good intestinal motility and an appetite, it is recommended to feed the horse with good quality hay only, at a rate of 1.2% of his live-weight over 4 to 6 meals a day (aim at 0.1 to 0.2% of live-weight per meal). Restricting energy intake just after surgery limits the risks associated with over-nutrition such as hyperglycaemia and septic shock.
    At the end of 2 to 4 days, depending on the state of health of the animal, the energy value of the ration can be progressively increased. A specific concentrate feed, suited to post-operative re-feeding can be given in addition to hay. We recommend therefore distributing 1.2% of the horse’s live-weight in good quality hay, and approximately 0.36L of REVERDY POSTOP for each 100kg of live-weight, divided between 4 to 6 meals a day.

Morgane ROBLES, Docteur en Sciences de la Vie et de la Santé.
Cyrille DAVID, Docteur Vétérinaire.
Department of Research and Development, REVERDY Equine Nutrition, Juvigny-le-Tertre, France

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