Managing the Risk of Colic in Horses

Colic in horses is a particularly frustrating problem to deal with as, in many cases, the cause is never confirmed. In fact, studies have shown that as many as three quarters of horse colic cases are undiagnosed. For this reason, several studies have sought to identify the risk factors associated with colic in horses; which usually involve collecting lots of data about how horses with colic are fed and managed and comparing it with data from horses that haven’t had colic. This can then be analysed statistically to show trends or factors that are associated with an increased risk of colic. Knowing these factors should help us to feed and manage our horses in ways that reduce the risk of colic.

The Risk Factors for Colic in Horses 

One of the first studies to determine risk factors for colic in horses was carried out by Tinker et al (1997) in the USA. Some of the key findings were as follows:

  • Changing the type of concentrate fed once a year increased the risk of horse colic by about 3.5 times
  • Feeding concentrates at between 2.5-5kgs per day increased the risk of horse colic by nearly 5 times
  • Feeding concentrates at more than 5kgs per day increased the risk of horse colic by over 6 times
  • Changing the type of hay fed more than once a year doubled the risk of horse colic

The obvious take-home messages from this study were that feeding concentrates and changing diet were two significant factors that increase the risk of colic in horses. So what can we do to mitigate these factors? Well, if you know your basic “rules of feeding” you can start to appreciate why they were developed. 

Key Rules to Consider in Relation to Colic in Horses

Make Changes to the Horse’s Diet Gradually

This allows the population of bugs that live in the horse’s digestive system time to adjust to the change of feed. The horse relies on the microbial population in the gut to digest fibrous material and changing suddenly from a high fibre to a high starch (cereal) diet or vice versa doesn’t give the bugs time to adjust. It is recommended to change the diet over 7 to 10 days. It may also be beneficial to use a prebiotic or live yeast supplement when making a significant change to the diet. Fungi such as yeast are part of the fibre digestion process and help to keep a stable environment in the gut whereas FOS prebiotics provide a food source exclusively for beneficial bacteria. Both would be beneficial to feed when the gut is being disrupted by a change of diet.

Feed Your Horse Little and Often

Although this study didn’t look specifically at meal size, keeping the total amount of concentrates fed to a minimum should help to reduce the risk of horse colic. It is recommended that a maximum of 1.25kgs and 1.75kgs of concentrates is fed per meal but if less can be fed then so much the better. It is preferable to feed 4 meals a day of 0.75kgs than two meals of 1.5kgs for example. By feeding more small meals the horse may be able to get more out of the feed he is consuming and so may require less feed in total – a win-win situation!

The other thing to consider is whether you actually need to use a cereal based feed at all? There are lots of ways to provide the energy your horse requires without having to resort to feeding cereals. High quality fibres such as alfalfa and sugar beet, provide as much energy as a cool mix – Dengie Alfa-A Original contains 10MJ/kg DE for example. When oil is added, such as in Alfa-A Oil, then the energy value increases to 12.5MJ/kg DE which is comparable to a competition or conditioning mix. Even if you don’t want to convert to a fibre and oil diet completely, reducing the amount of cereal based feed will reduce the risk of horse colic.

Colic in Horses: Findings from More Recent Studies

In a study by Scantlebury and colleagues, published in 2014, more risk factors have been identified. In this study, 59 recurrent horse colic episodes and 177 controls were included. One of the interesting findings was that a linear relationship exists between the amount of time a horse was turned out and the risk of colic. 

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For example, a horse that is always stabled had twice the risk of recurrent colic compared to a horse with 12 hours of turnout per day. It goes without saying that turning horses out tends to be beneficial but if this isn’t possible then ensuring plenty of forage is available when they’re stabled is of paramount importance. Horse owners often assume that “ad lib” means feeding lots of forage but what it actually means is that the horse is never without access to forage. There aren’t many horses that haven’t eaten all of the forage available to them over night by the next morning which technically means they haven’t been fed “ad lib”.

Restricting access to forage may be necessary for good doers to stop them putting on too much weight. In these situations feeding forage little and often should help to keep the time the gut is empty as short as possible which should be beneficial for not only reducing the risk of colic but other issues such as gastric ulcers too.  

Horse Colic: Further Work Required

Horse crib bitingAn area that stimulates considerable debate is the possible link between crib-biting and/or windsucking and colic. Known collectively as stereotypic behaviour, the exact reasons why horse’s wind-suck or crib-bite is still not fully understood. Anecdotal reports suggest a reduction in wind-sucking and cribbing behaviour often occurs once gastric ulcers are treated. As one of the many symptoms of ulcers can be colic, particularly recurrent colic, further work is clearly required to explore the relationship between the presence of ulcers and colic.   

Further information can be found in the studies and information cited in this article:

Proudman, C.J. (1991) A 2-year prospective survey of equine colic in general practice. Equine Vet. J. 24, 90-93.
Scantlebury, C.E., Archer, D.C., Proudman, C.J. and Pinchbeck, G.L. (2011) Recurrent colic in the horse: incidence and risk factors for recurrence in the general practice population. Equine Vet. J. 43, Suppl. 39, 81-88.
Archer, D.C. and Proudman, C.J. (2006) Epidemiological clues to preventing colic. Vet. J. 172, 29-39.
Tinker, M.K., White, N.A., Lessard, P., Thatcher, C.D., Pelzer, K.D., Davis, B. and Carmel, K. (1997) Prospective study of equine colic risk factors. Equine Vet. J. 29, 454-458.
Nadeau, J.A. and Andrews, F.M. (2009) Equine gastric ulcer syndrome: the continuing conundrum. Equine Vet. J. 41, 611-615.
Hillyer, M.H. and Mair, T.S. (1997) Recurrent colic in the mature horse: a retrospective review of 58 cases. Equine Vet. J. 29, 421-424.
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