Diet Recommendations for Horses Prior to Surgery

Humans undergoing surgical or medical procedures are often given strict instructions regarding fasting beforehand. Similarly, many equine surgeons provide horse owners with specific guidelines for withholding feed prior to surgery. According to a recent review on feeding horses prior to surgery, however, there is a delicate balance between too much and not enough of a good fast.

“Fasting is frequently recommended for elective laparoscopic procedures such as ovarietcomy, biospy, castration, removal of bladder stones, and even some colic cases,” said Peter Huntington, B.V.Sc., M.A.C.V.Sc., director of nutrition at Kentucky Equine Research (Australia).

“Current recommendations for fasting prior to surgery are highly variable depending on the surgeon and the procedure the horse is scheduled for, ranging from 12–24 hours,” he added.

When maintained on pasture, horses typically graze for approximately 16 hours in a 24-hour period. Withholding feed from horses can be problematic because fasting:

• Can be stressful;
• Contributes to the formation of gastric (stomach) ulcers;
• Potentially alters physiological characteristics, including hydration status and heart rate; and
• Might be associated with various stereotypies.

In addition, excessive fasting prior to surgery can actually predispose horses to colic in the postoperative period, especially the development of typhlocolitis or inflammation of the cecum and colon.

Despite those drawbacks, there are some important reasons for fasting horses prior to surgery, especially laparoscopic surgery.

As described in a recent study*, fasted horses have less gas in their gastrointestinal tract, which decreases the chances of the surgeon puncturing the intestine with the trochar, a sharp instrument that serves as a portal for surgical instruments. Intestinal tissue with less gas also allows the surgeon to visualize the organs inside the abdomen better than a larger, gas-filled gastrointestinal tract.

In their study, Zebeli and coworkers reviewed the available literature on fasting, gastrointestinal transit time, and gas production. Based on their extensive literature review, they made the following recommendations:

• Feed stem-rich hay that is higher in fiber and is low in easily fermentable carbohydrates, such as fructans;
• Offer small portions of that hay every 2 hours until 26 hours (or less) prior to surgery; and
• Supplement the diet with oil, which may help decrease gas production.

That said, owners are encouraged to avoid abrupt changes in diet whenever possible. Discuss any changes in diet related to a surgical or medical procedure with your veterinarian before making any alterations.

*Zebeli, Q., J. Keßner, V. Kliseviciute, et al. 2015. Dietary approaches top optimize the fasting period before laparoscopic surgery in horses: An overview. Journal of Equine Veterinary Science. 35:701-708.