Maximising Digestive Health: Colic

Maximising Digestive Health: Colic

Bay horseWhilst a horse may be large, its digestive system is delicate and digestive health is vital for the overall health of the horse (Geor, 2005). Having evolved to graze for 16-18 hours a day, this delicate system adapted to consume a high fibre, low starch diet. Whilst high levels of exercise may mean that forage alone may no longer meet the horse's energy requirements, modern feed and management practices can compromise digestive health.








  • How can diet increase the risk of colic?

    Starch overload - Undigested starch entering the hindgut as result of feeding large amounts of cereals is rapidly fermented, leading to rise in lactic acid and lactic acid producing bacteria. The subsequent drop in pH may cause inflammation of the barrier lining the gut (and possible absorption of toxins through the gut wall) and/ or a reduction in fibre digestion microbes and consequently fibre digestibility.

    • The risk of colic has been seen to be almost 5 times greater in horses fed 2.5-5kg of concentrate feed per day and approximately 6 times higher in horses fed more than 5kg of concentrate feed per day (Tinker et al 1997). Furthermore, cases of colic were found to be 2.6 times more likely following a recent (previous 2 weeks) change in feed (Hudson et al 2001) and 2.2 times more likely as a result of multiple feed changes in the last year (Tinker et al 2007).
    • Changes in forage source may also increase the risk of colic.
    • In a recent study, stabling and feeding hay led to drier faeces and decreased gut motility (intestinal contractions), despite increased water intake (Williams et al 2014). In other studies, the risk of colic was found to be approximately 5-10 times higher as a result of changes in hay source (Hudson et al 2001, Cohen et al 1999).
    • Grazing - Horses without grazing or subjected to a recent decrease in grazing were found to be 3 times more likely to suffer from colic in general (Hudson et al 2001), although inflammation of the small intestine (duodenitis-proximal jejunitis) is more common in grazing horses (Cohen et al 2006). In another study, the risk of colon impactions and displacements was approximately 30 times higher in horses withoutaccess to pasture (Hillyer et al 2002).
  • How you can help

    Reduce starch intake

    Avoid feeds containing high levels of cereal starch. For those unable to maintain weight on ad lib forage alone, look for feeds containing high levels of digestible fibre and oil. Gram for gram, oil is approximately 2.5 times higher in energy (calories) compared to cereals and starch free.

      • Feed small meals
      • Feed no more than 400g of feed per 100kg bodyweight per meal (up to 2kg) i.e. 2kg per meal for horses 500kg and over.
      • Take care to warm up and cool down properly before and after exercise.
      • Aim to reduce stress wherever possible including during exercise, turnout and transport.
      • Do not feed in anticipation of an increase in workload – wait until additional energy is needed before increasing intake.

    Dietary advice

      • Forage : The foundation of the diet
      • Forage should ideally be fed ad lib although if the risk of excess weight gain makes this impractical, a minimum daily intake of 15g per kilogram bodyweight per day dry matter is recommended. In general, providing grass turnout seems to reduce the risk of colic although it is worth remembering that short periods of turnout without a muzzle may lead to 'gorging' which in turn could present an increased risk. Turn out on frosty grass should also be avoided for colic prone horses. Mature/ 'stemmy' forages contain higher levels of indigestible lignin and should therefore be avoided, particularly for colic prone animals. Whilst feeding straw as a partial forage replacer may be useful for good doers, some nutritionists recommend that straw should account for no more than 30% of the horse's total forage supply and if used, should be introduced very gradually.
      • Avoid rapid or frequent changes in diet
      • Ideally introduce all changes in pasture, hay and haylage over a minimum of two weeks. As a guide, replace old feed for new at rate 100g per 100kg of bodyweight (maximum 500g) every other day i.e. 500g every other day for horses with an estimated bodyweight of 500kg and over.
      • Do not feed mouldy feed for forage
      • Inspect all feed and forage for visible signs of mould regularly. In one study almost 30% of hays fed to horses that developed colic were of poor hygienic quality vs. only 3% of hays in horses without colic (kaya et al, 2009).
  • References
      • Cohen, N.D., Gibbs, P.G., Woods, A.M., 1999. Dietary and other management factors associated with colic in horses. Journal of American Veterinary Medical Association 125 (1) 53-60.
      • Cohen, N.D., Toby, E., Roussel, A.J., et al., 2006. Are feeding practices associated with duodentitis-proximal jejunitis? Equine Veterinary Journal 38 (6), 526-531.
      • Geor, R.J. (2004) Nutritional management of the equine athlete. In: Equine Sports Medicine and Surgery. Eds Hinchcliff, K.W., Kaneps, A., and Geor, R.J. Saunders USA , pp 815-835.
      • Hillyer, M.H., Taylor, F. G., Proudman, C. J., et al., 2002. Case control study to identify risk factors for simple colonic obstruction and distention colic in horses. Equine Veterinary Journal 34 (5), 455-463.
      • Hudson, J.M,, Cohen, N.D., Gibbs, P.G., et al., 2001. Feeding practices associated with colic in horses. Journal of American Veterinary Medical Association 219 (10), 1419-1425.
      • Kaya, G., Sommerfield-Stur, I., Iben, C., 2009. Risk factors of colic in horses in Austria. Journal of Animal Physiology and Animal Nutrition 93 (3), 339-349.
      • Tinker, M.K., White, N.A., Lessard, P., et al., 1997. A prospective study of equine colic risk factors. Equine Veterinary Journal 29 (6), 454-458.
      • Williams, S., Horner, J., Orton, E., Green, M., Mcmullen, S., Mobasheri, A., Freeman, S.L. 2014. Water intake, faecal output and intestinal motility in horses moved from pasture to a stabled management regime with controlled exercise. Equine Veterinary Journal 47 (1), 96-100.