November 21, 2012
Colic refers to abdominal pain in horses, which can occur for many reasons including impaction, sand ingestion, twisted gut and more. In a hospital (veterinary clinic) setting, colic diagnosis may include a laproscopic examination or flank surgery or major abdominal surgery. Other techniques available at a larger clinic may involve ultrasound. But in the field, or at a small clinic, tools and techniques are often limited to things like trans-rectal palpation, listening to gut sounds with a stethoscope, and doing a belly tap. The basic examination will include checking heart rate, respiration rate, capillary refill time (checking the gums), etc. to see how shocky the horse may be.
"Often you are trying to decide early on if surgery (or a more lengthy and involved diagnostic procedure) is needed, and you also have to determine if this is something the horse owner would want to do, and could afford. You have to make these determinations as quickly as possible, to give the horse a chance," said Cid Hayden, DVM, Salmon, ID.
One of the primary techniques used by veterinarians for colic diagnosis is palpation per rectum. The veterinarian gently reaches into the rectum with a well-lubricated plastic glove/sleeve, to try to feel some of the adjacent portions of the digestive tract and other organs—to help determine what is going in inside the animal.
Dr. Hayden said this procedure is not without risk and should never be attempted by an untrained person. Palpating a horse is considerably different than palpating a cow. The rectal tissues of a horse are much more delicate and bowel contractions are very strong.
nt Colic refers to abdominal pain in horses, which can occur for many reasons including impaction, sand ingestion, twisted gut and more.
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"Cows are tough and durable and their bowel contractions are relatively weak. Horses are more fractious, and cows are more placid. The horse may be jumping around more and straining harder against the intruding arm. This, plus the delicate tissues, could lead to injury of the rectal tissues," he said.
"If done correctly and carefully, the risk is minimal, but there is always a chance for mild irritation and inflammation of tissues, or even rectal tears. Those can be very serious, requiring emergency abdominal surgery to correct," explained Dr. Hayden.
"In an animal that has colic, the risks are greater. The horse already has abdominal pain, and may have a lot of pressure due to a distended bowel. There may be an impaction, or a sore spot that would cause the horse to react if you bump into it. If you are palpating a horse for a colic examination, you could run into more potential problems, as well as more difficulty in doing the palpation itself," he said.
"When trying to check the internal areas of the abdomen, no one has an arm long enough to feel the entire abdomen of a horse. You are usually palpating the rear one-third at best. You can't feel everything you need to check. You are trying to feel for an abnormality or for a normal organ that's not where it's supposed to be," said Dr. Hayden.
"In those situations it's not so much that you can feel what's wrong, but the normal anatomy is not where it is supposed to be – or if it's missing, where did it go?" The veterinarian may be able to interpret certain displacements.
"Some of the examination for colic, per rectum (trying to figure out what is wrong) takes a lot of interpretation—based on what the normal anatomy would have been. In a small town practice like ours (more than 100 miles from an equine hospital), if it's a serious case where the horse needs surgical correction, this means hauling the horse somewhere else.
"Color of the gums and other color changes can be also clues regarding whether the horse is becoming toxic from endotoxin release or other problems," says Hayden.
Listening to the abdomen with a stethoscope can reveal gut sounds – whether or not there are any gut sounds, their frequency, and the type of sounds. "A horse that has no gut sounds means that things are shut down, which is not a good sign," he says.
A belly tap (inserting a sterile needle through the belly wall to obtain fluid) can tell the veterinarian several things. "We check for white blood cells and inflammatory cells, fibrin and such. We can also do some other tests on that fluid, to get an idea about how serious the horse's condition might be," he explains. A thorough examination of a colicky horse consists of many little bits of information, to put together to try to see the larger picture.
One of the things the veterinarian will ask is whether the horse is passing manure. The horse may pass a little manure at first and then cease – if there is something serious farther up the tract that is causing blockage or shutdown. An examination of the manure may give clues. "If it's very dry, this can be an indication of problems. Sometimes it might have sand in it," he says.
The history of the horse can also be very helpful. "The horse may have gotten out into an alfalfa field, for instance. One problem we encounter fairly often with people packing into the backcountry is change of feed. They bring the horse from home where he's been on hay or pasture and feed some type of packer pellets, which are super dense and very dry. When the horse eats a bunch of those and then drinks water, they expand in volume. I commonly see horses that people bring down out of the mountains acting colicky, and as soon as I find out they've fed the horse pellets, I treat those horses for impaction," he says.
"Another thing a person should learn how to do – which is helpful in any serious condition – is take capillary refill. Lift up the lip, find a pink spot on the gum and press it for a few seconds with your thumb. Take your thumb away and see how quickly it turns pink again. It should turn pink in two seconds or less. If it takes three seconds this indicates a little shock, four to five is mild shock, and seven seconds or longer indicates severe shock."
"I tell people that if they have a colic situation, they should check vital signs. Every horse owner should invest in a stethoscope and learn how to use it. You need to know what your horse's normal heart rate and respiration rate is, and listen to bowel sounds. Even though owners may not be able to differentiate between types of breathing and types of pulses and types of gut sounds, they can count bowel contractions and gurgles – how many per minute. If you write down somewhere (for each horse) what his normal heart rate, respiration rate and gut sound rate is, this gives something to compare to in an emergency. You can check those three things and after you walk the horse around check again. If those aren't going back toward normal after an hour, call your veterinarian," he explains.