By Naomi Barrett
Your horse is pawing at the ground, sweating and looking around at his flank, repeatedly getting up and down and rolling as well. These tell tale signs can strike fear into the heart of any owner as they are typical symptoms of colic and although the majority of colic cases are not serious, it remains a leading cause of death in horses worldwide.
Rather than being a disease in itself colic is actually what we call a ‘clinical sign’ that presents when a horse is suffering from any kind of abdominal pain. This pain often arises from problems relating to the gastrointestinal tract, but can also be caused by problems with other abdominal organs such as the liver, kidneys or ovaries. It may also vary in intensity from a slight belly ache to extremely acute pain. Consequently the signs associated with the pain can vary too, from sluggishness, decreased appetite, and general signs of stomach ache (i.e. pawing the ground, kicking at the belly or examining the flanks) in milder cases to groaning, sweating, rolling and even thrashing and swelling of the abdomen in more severe cases.
There is a myriad of different causes of colic, too many to cover in just one article, but I will give a brief overview of some of the more commonly seen types. Occasionally the muscles of the intestines will contract abnormally and over-actively in painful spasms. This spasmodic colic is the most frequently seen type and often occurs after changes in diet and management, however some horses seem particularly prone and there is not always an identifiable trigger. Fortunately, though common, it is usually easily resolved with muscle relaxants to calm the spasms.
An unusual build up of gas causing the wall of the intestine to become stretched and distended results in tympanic colic. This may be the consequence of consuming a rapidly fermentable feed such as a flush of new grass, excessive hard feed or even too many apples. Horses that spend most of the day confined to a stable are more likely to develop this sort of colic. Such horses are also at greater risk of impaction colic, where their food forms into a firm mass that causes a blockage within the bowel, particularly at points where the intestines are naturally narrower or experience a sharp turn. Again this is normally resolved without too much trouble by the administration of fluids through a stomach tube. Only in a few more severe cases may it be necessary to perform surgery to remove the impaction.
The most serious types of colic are those that are caused by an obstruction of the blood supply to the intestine, as without this essential supply the area of affected bowel will rapidly die. Sadly the anatomy of the horse, where long sections of intestine are either suspended in place by lengths of freely movable tissue or unattached to the body wall, is such that there are multiple ways in which this scenario can potentially occur. Parts of the bowel may become displaced, moving to an abnormal part of the abdomen, or the bowel may undergo torsion where it twists on itself. Thankfully these events do not happen very often, but are extremely serious, typically requiring rapid surgical intervention when they do arise.
Unfortunately, the early stages of these life-threatening colics can present in a similar way to those that are less serious, which is why it is advisable to contact your veterinary surgeon at the earliest indication of abdominal pain. Once you have done this then it may help to move your horse your horse to a safe place, such as a sand school or deep bedded stable, where they are less likely to be injured should they roll and can be more easily observed. If a horse is determined to roll, walking them around gently will equally prevent them from causing any self trauma, distract them from the pain and potentially remove trapped gas as well. Remove any feed and remember to watch out for your own safety as well.
Useful things that your vet may want to know when they arrive will include what signs of colic the horse has been showing, for what duration of time, whether your horse has suffered from colic in the past and, if so, how it resolved. They will want to know of recent dietary or management changes as well as your horse’s worming and general medical history. Knowing when your horse last ate and drank and if he has passed any droppings is also important.
Examination of the colicking horse encompasses the whole animal to enable your vet to determine the most appropriate course of treatment. This will involve checking the heart rate, which, if elevated above the normal 20-40 beats per minute, is suggestive of pain and can even reflect the severity of the pain. The colour and moistness of the gums (mucous membranes) will be checked and the capillary refill time assessed by pressing on the gums and waiting to see how long the colour takes to return, giving an indication of the hydration status and blood perfusion of your horse. Normal gums will be pink and moist with a capillary refill time of less than 2 seconds. Pinching up a section of skin and watching the length of time before it returns to normal can be used alongside the gum parameters and other things such as sunken eyes to establish hydration status.
Your vet will also listen to your horse’s gut sounds through a stethoscope applied to the upper and lower, left and right sides of the abdomen. The sounds typically reflect the level of activity taking place in the intestines and can be increased, normal, decreased or even completely absent. Rectal examination is frequently performed, usually under sedation, and enables palpation of what is going on inside the abdomen. Though limited by how far the arm can reach, major abnormalities such as a food impaction or distended areas of bowel due to a twist can potentially be detected.
Further information may be gained by passing a nasogastric tube up the horse’s nose and into its stomach looking for gastric reflux. This occurs when an intestinal blockage results in the accumulation of fluid in the stomach since horses are unable to vomit to relieve this build up. Gastric reflux typically means a horse will require surgery, but if not present then treatment can be administered via the nasogastric tube. A sample of fluid from the abdomen can be obtained via a needle in a procedure known as abdominocentesis, which can give another indication of bowel health.
Taken together the results of this examination will allow your vet to make the decision as to whether your horse can be treated medically or if they will require referral for surgery. Fortunately, as mentioned before, most colic cases are not life-threatening and will respond well to treatment on the yard, with pain relieving drugs being the mainstay therapy. For those situations where surgery is deemed to be necessary the chances of a successful outcome are greatly improved if the surgery is performed as soon as possible after discovering the problem.
Taking sensible precautions such as avoiding sudden management/diet changes can help to reduce the risk of colic, but horses as a species are predisposed to this condition due to their unusual anatomy and physiology, which means that even the best kept animal can suffer from it.
If you have any questions about any aspects of your horses’s health, or indeed your pet, farm or smallholding animals, please do not hesitate to contact us on 01892 835456. Putlands Veterinary Surgery is based in Paddock Wood in Kent, and offers a friendly, proffessional and personal service for all species of animal. We have four dedicated large animal vets with a wealth of equine experience between us, and are always happy to help.