Older horses more likely to need surgery
Older horses were more likely to require surgery than younger horses, based on the data from New Bolton Center. Geriatric
horses were one-and-a-half times more likely to undergo surgery and three times more likely to be subjected to euthanasia
after medical management compared with mature horses. The higher occurrence of strangulating lesions (particularly small intestinal
strangulating lesions), combined with their tendency toward less dramatic signs of colic, should be taken into consideration
when evaluating these patients, to avoid any treatment delay.
"Given that older horses may be more critically ill, and may be more likely to require surgery, referring them sooner may
reduce the number we have to euthanize during surgery because we waited too long," Perrier says.
Southwood suggests owners and veterinarians keep in mind that older horses showing signs of colic could have a strangulating
lesion. "When I have an older horse, one in its late teens or older, come into the hospital, I initially presume it has a
strangulating lesion, and I approach it by proving to myself the horse does not have a strangulating lesion," Southwood says.
"The diagnosis is based on the signs of pain, history, physical exam, laboratory data, palpation per rectum, abdominal ultrasonographic
examination, nasogastric reflux and peritoneal fluid analysis."
If she proves to herself the horse doesn't have a strangulating lesion, then she treats it medically. The goal, she says,
is to get these horses to surgery as soon as possible to optimize the chance of having a favorable outcome. "Sometimes we
can get them early enough that we don't have to resect the bowel," she says. "The flip side is we don't want to take horses
to surgery unnecessarily, and that's where carefully assessing the clinical findings is important, but it's often challenging."
Looking at short-term survival of emergency admissions, the main reason geriatric horses had a lower survival rate compared
with mature horses is likely because owners elect euthanasia without surgery. This decision may be due to poor prognosis for
survival based on physical examination and laboratory data at admission, perceived poor prognosis based on age or the unwillingness
of an owner to make a financial investment in an aged horse. Geriatric horses, even those in their late teens and early 20s,
requiring surgery for a strangulating lesion do not have a less-favorable prognosis for survival compared with mature horses.
Therefore, a poor prognosis based on age alone, or election of euthanasia based on age alone, is inappropriate.
"Now when I'm talking to an owner, I feel I can give him or her as much accurate information as possible and advise that he
or she does not necessarily need to euthanize the horse just because it's 24 years old," says Southwood. She notes that euthanasia
still may be indicated if an owner can't afford surgery or if the horse has other serious underlying disorders.
The take-home message
The study concluded that if you look at the overall population of horses with colic, both geriatric and nongeriatric, the
geriatric horses do have an overall lower survival rate, but that includes those euthanized without surgery and those euthanized
From the total population, if you take out the number of horses euthanized before or during surgery, there was no difference
in the survival of the geriatric and nongeriatric mature horses, and that included horses more than 20 years of age. "When
we looked at the ones with small intestinal lesions where the owners decided to go on with surgical repair, we did not see
a difference in survival," Southwood says.
Southwood recently did colic surgery on a 32-year-old horse. "He had a strangulating lipoma, and we removed about 12 feet
of small intestine. The horse had no complications after surgery. He never missed a beat," says Southwood. "He is currently
at home doing well."
The take-home message: "Early referral and surgical intervention, when necessary, is really important," says Southwood. "These
older horses, especially those with small intestinal lesions, can do very well with surgery."
Kane is a researcher and consultant in animal nutrition. He is an author and editor on nutrition, physiology and veterinary
medicine with a background in horses, pets and livestock. He is based in Seattle.
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