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Let Them Eat: Horses Undergoing Non-Abdominal Surgery May Be Better Off Eating

Much like human doctors, veterinarians often recommended that horses slated for surgery fast before undergoing anesthesia. In humans, this reduces the risk of the development of aspiration pneumonia; in horses it was thought to decrease the risk of post-operative colic. However, a study has shown that there may be no need for horses scheduled for non-abdominal surgery to refrain from eating.

A retrospective study over a two-year period used 1,965 horses older than two years old that were referred to the Oakridge Equine Hospital in Edmond, Okla., for non-emergency, non-abdominal procedures. The horses had not fasted prior to their surgeries.

Dr. Patricia Baily and her study team found that only 2.5 percent of the horses that had not been fasted became colicky. They also found no correlation between the age of the horse, the surgery performed or the duration of the anesthesia and colic risk.

The scientists conclude that allowing a horse to eat prior to undergoing general anesthesia for a non-abdominal surgery doesn't increase his colic risk. In fact, allowing the horse to eat may help him maintain gut motility, reducing the risk of post-operative colic.

Study: South African Swine Vaccine Can Limit Castration Complications

Surgical castration of intact male horses is common throughout the world, but the routine surgery isn't always complication-free. A South African study led by Dr. John Birrell investigated the use of a GnRH vaccine (sold under the name Improvac by Zoetis in South Africa) prior to castrating 19 colts. The study sought to determine if the vaccine could reduce testis size and therefore minimize the risk of surgical complications.

GnRH is an immunocontraception vaccination – it's a birth control that uses an animal's immune system to mount a response against the reproductive process.

The colts were divided into three groups. Two groups received the GnRH vaccine and were castrated 57 and 100 days after receiving the two-part vaccine while the third group acted as a control. The testis of each horse was measured for length, width and height on days 0, 28 and 57 or 100 depending on when the horse was gelded. The horses were also monitored for 10 days after the surgery for complications like swelling, surgical site discharge and depression. The horses also had both their testosterone concentrations and anti-GnRH titers measured.

The GnRH vaccinated colts had no fevers, swelling or lameness after vaccine administration. They also had a decline in testosterone levels after the first vaccination; testosterone was undetectable 28 days after the second dose. The vaccinated horses had a 50 percent reduction in testicular volume prior to castration and they also had no post-surgical complications.

The study team concluded that GnRH vaccine administration reduced testicular size and was helpful in controlling post-surgical complications. They noted that the GnRH vaccine could be used to control undesired behavior in stallions.

The Lowdown On Lipomas And Surgery Survival

Colic is a broad term that is often used to indicate any type of abdominal pain, but veterinarians can often determine — or at least narrow down — what is causing the abdominal issue. One common cause of colic, particularly in older equines, is a strangulating lipoma.

A strangulating lipoma is a benign, fatty tumor on a stalk that can wrap around and strangulate a section of small intestine. There are no good markers to denote a horse that may be at risk of a lipoma other than advancing age. The only repair for this type of colic is surgery.

When the veterinarian has the horse on the table, he or she will prophylactically remove all of the lipomas found in the small intestine and small colon to prevent strangulation in the future. Older horses tend to be more stoic so may not show the intense pain they are in. For this reason, some strangulating lipomas are missed during vet exams.

It's imperative that if a horse is suspected to have a strangulating lipoma that he is sent directly to an equine hospital equipped to handle surgery. The idea that older horses don't handle colic surgery and anesthesia well is a myth, according to EQUUS magazine. Older horses have as good of a chance of survival after colic surgery as younger horses.

Horses That Struggle With Attention May Be Battling Pain

Horses that ignore their surroundings (including their handlers) may not be cranky or depressed—they may be in pain. Drs. Louise Dodds, Laura Knight, Kate Allen and Joanna Murrell created a study that tested the reactions of 20 horses to novel objects and sounds just before and after they underwent a surgical procedure. They compared the surgical horse's reactions to those of 16 control horses who didn't have surgery.

The research team found that the surgical horses spent significantly less time interacting with a pool noodle and a flipper immediately after surgery than they did before the surgery. There was no difference in interaction times in the control horses when they encountered the objects a second time.

Surgical horses also were less likely to react to the noise of a hair dryer after surgery than before. The response of the control horses did not change from one exposure to the next.

The scientists conclude that pain effect a horse's response and startle times. Exposing the horse to a situation that demands attention may be a useful biomarker of pain, they say.