Colic is the leading cause of death in horses, and it tends to affect our senior citizens are a higher rate. Coupled with that concern is that colic surgery may be less successful for older horses and due to its high cost, major colic in older horses often results in euthanasia.
Colic is really just a term to describe abdominal pain, and that pain can be minor due to some gas build-up or a small blockage, or major due to twisting of the gut, large blockages and/or intestinal tissue death. It is these latter types of colic that often require surgery. In many milder cases of colic, pain relief and medical interventions to reduce gas or release blockages are sufficient. Regardless, when colic strikes our horses, young or old, it is scary.
As indicated, colic tends to affect older horses more commonly than younger horses. A study from Germany looked at almost 1,000 horses that were admitted to a veterinary clinic for colic symptoms. Of these horses, the average age was 19.9 years. Most horses were only treated medically, and these had a better survival rate than those that had to undergo surgery.
A common surgical finding in horses between the ages of 21-29 was strangulating lipomas. These are fatty tumors that tend to develop in a horse’s abdomen that can grow to a point where they become heavy, weighing down parts of the digestive tract, and can even “loop” around areas to strangulate either the intestines themselves or the blood flow to them. These types of tumors are not associated with equine obesity, so there is no way to prevent them or even to detect if they are developing.
There are other risk factors for colic that are associated with feeding and management. Knowing what they are can be a potential strategy to help prevent colic.
A thorough review of colic studies was conducted in 2019 and reported “odds ratios” (OR) where a higher number indicates a higher risk associated with that factor. Horses that crib or windsuck had higher risks of colic, along with a higher risk of a particular type of colic (epiploic foramen entrapment, a type of small intestinal strangulation) and an OR ranging from ~8 to ~70! Housing also increased the risk of colic, with increased stall time and/or recent changes in stabling increasing the risk (OR ranging from ~1-5).
Changes in diet (hay or grain) increased the risk of colic (OR ranging from 2-10), and horses that were fed higher amounts of grain/concentrate also had higher risk ‒ eg. 2.5-5 kg of concentrate had an OR of 4.8, while more than 5 kg had an or of 6.3. Feeding alfalfa hay increased the risk of colic (OR 4-10), as did the feeding of coastal hay (OR 1.3-5.7).
Dental issues also increased the risk of colic (OR 5-7). Oral problems are particularly important for our older horses. As horses age, they continuously erupt a long tooth that is embedded in their skull at birth. When horses start to reach their 20s, there can be less tooth remaining, and they remaining stubs can fall out altogether. Therefore, older horses may have problems chewing and breaking down their feed adequately, leaving longer particle sizes to work their way through the intestinal tract and increasing the risk of these particles to get stuck and cause a blockage.
Working closely with your vet to examine your horse’s teeth can help give you an idea of what you’re working with and how dietary management may need to change.
Typically, with less tooth surface available for grinding, feed manufacturing needs to do the job for them. So products like hay cubes or even pelleted hay/roughage chunks, can have relatively small particle sizes already, and when soaked in water can create a slurry that can be consumed easily.
Other high-fiber feeds such as beet pulp and rice bran are also good to mix in. From there, you may need to add in a ration balancer or other feed depending on the horse’s individual nutrient requirements, and oil can be added to increase calories. Of course, all horses should have plenty of fresh water available at all times, and have lots of turnout.
Unfortunately, despite our best efforts, colic will affect 1 in 10 horses in their lifetime. When it hits our older horses, the overall outcome tends to be less favourable. With good management and feeding practices we can do our best to decrease the risk, but unfortunately sometimes colic just happens for no apparent reason.