Large colon torsion – is your horse at risk?

This week, Horse and Hound magazine wrote an article on colic. Colic affects many horse owners, if it is a bad case of colic it can be fatal. I thought this was quite an interesting article as many horse owners can relate. For myself, both of my horses have had colic once. One case was serious and my horse had to stay over at the RVC veterinary hospital where they took great care of her, the other a mild case where my horse recovered with the antibiotics and pumping through of the gut.

Torsion, or twisting, of the large colon is one of the most painful and serious forms of colic in horses. it accounts for more than 15% of colic surgeries and even when there is quick surgical intervention to untwist the colon, it can still be fatal.

The equine colon is a large U-shaped organ, usually 3-3.7m in length with a capacity of over 100l. Despite its size however, the large colon is very mobile. It can twist about itself up to 180 degrees within the horse’s abdomen, without causing the animal a problem.

If the colon twists more than 270 degrees, it cuts off its own blood supple, which impairs or compromises its normal protective barrier function. This allows large quantities of toxins into the horse’s circulation.

Even when the colon is untwisted or removed during surgery, the horse can remain in toxic shock. This is why the condition is often life-threatening even after surgical intervention. Until now, there has been little information about which horses are most likely to be at the risk of this serious form of colic.

However, new research funded by the Horserace Betting Levy Board and performed at the University of Liverpool, has identified factors that could increase or decrease the risk of large colon torsion occurring. Taking on board these factors will enable us to be more proactive in preventing this condition.

How the study worked

Over a two year period, vets at Liverpool recruited 70 owners whose horses had suffered from large colon torsion and more than 200 randomly selected control (non-affected) horses from four large equine hospitals in the UK.

For each of these horses, a phone questionnaire was completed with the owner or carer of the horse. The horse’s size, type and use, its medical breeding and history, its stabling and turnout regime, its diet, level of exercise, behaviour and preventive health care was recorded.

The researchers statistically analysed this information, which allowed them to identify factors that were significantly associated with an increased or decreased risk of horses suffering from large colon torsion.

Who was at risk? The study showed some interesting results:

Broodmares were 13 times more likely to develop large colon torsion colic than geldings and stallions. In addition, the majority of cases of large colon torsion in broodmares occur in the three-month period after foaling. This may be due to the sudden increase in the potential space within the abdomen after foaling for the colon to move around, or may be due to various management changes that occur around the time of foaling.

Tall horses were also found to be at an increased risk – a 17hh horse was eight times more likely to suffer from a large colon torsion than a 13.2hh pony. This may reflect a difference in the relative dimensions within the abdomen of horses and ponies.

Serial colic sufferers with a history of multiple colic episodes in the last year were nine times more likely to develop large colon torsion, compared with horses that had not suffered at all. This last finding, in conjunction with previous research, suggests that some horses have an underlying abnormal functioning of the large colon, predisposing them to multiple colic episodes.

A change in routine: horses who have a change in routine – specifically those who were stabled for longer periods in the previous two weeks – were found to be at greatest risk. A number of past studies have shown that reduced time at pasture can increase the risk of colic occurring, as it reduces the mobility of the large colon. The lesson is that horses should be turned out as much as possible, even in winter. This is particularly important in horses who are already at increased risk of colon torsion, such as broodmares or those that have previously had colic.

Quidders – horses that drop their feed while chewing – were eight times more lively to develop large colon torsion compared to horses that did not. Quidding is normally the result of dental problems, such as sharp enamel points or diastemata ( gaps) between the teeth. it is therefore wital that every horse has regular, at least every 12 months, dental examinations. These should be performed by a vet or by an equine dental technician who is a member of the British Association of Equine Dental Technicians.

Three or more carers: horses with this number of carers were found to be at increased risk. This may be due to less consistent feeding or management regime when multiple people are involved in a horse’s care. Large numbers of horses on a premises was also associated with increased likelihood of large colon torsion, which could also be due to lack of consistency in stable routine. A recent change in pasture and the amount of hay or haylage fed also increased the risk of large colon torsion. These findings highlight how important it is to make any changes to your horse’s management and diet as slowly as possible. You should take at least two weeks to do so.

Sugar beet : horses fed sugar beet were more likely to suffer from large colon torsion. Sugar beet is a carbohydrate that rapidly ferments in the horse’s colon and feeding it – or other concentrates high in carbohydrate – has the potential to cause an imbalance in the populations of bacteria within the horse’s gut. Feeding only as much concentrate as necessary is an important management consideration. Many horses in light or moderate work just need hay or haylage and grass to maintain condition and provide them with enough energy.

Preventative measures

While it is impossible to guarantee that colic can be prevented in every horse, this study has highlighted those individuals more at risk of large colon torsion. It has also shown that, by paying close attention to your horse’s management regime, it is possible to significantly reduce the risk of him suffering from this particularly serious form of colic.



One thought on “Large colon torsion – is your horse at risk?

  1. Re sugar beet: I notice that some feeds contain high levels of sugar beet pulp with no advice to soak it on the bags or statutory statement. Could this account for some colic cases?Particularly where pps don’t think about the amount of beet they are giving?
    British horse society manual indicates sugar beet should always be soaked; depending on the product depends the time it should be soaked.

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