Bringing malnourished or starved horses back to a healthy state and an appropriate body condition score (BCS) calls for careful management and close collaboration with a veterinarian. Horses with a BCS of 3 or lower or a history of inadequate feeding need a structured refeeding protocol.

Refeeding Syndrome in Horses

Sudden overfeeding of a severely malnourished horse triggers a condition called refeeding syndrome, which leads to metabolic disturbances that can have deadly effects.

“If you have a starved horse, and you throw a bunch of feed at it because you know it needs to gain weight, their body basically goes into shock because they cannot handle all of the extra nutrients,” says Carey Williams, PhD, extension specialist and professor at Rutgers University, in New Brunswick, New Jersey.

“When calories are inadequate, the horse’s metabolism breaks down their own protein for survival,” adds Stephanie Whalen, DVM, a veterinarian at Troy Equine Services, in Ontario, Canada. “Refeeding syndrome can occur if they are quickly refed, particularly with carbohydrates. The switch to carbohydrate metabolism changes how the body uses electrolytes. This leads to electrolyte imbalances which impact nerve and muscle function, including the gastrointestinal tract, heart, and breathing muscles. The medical complications are numerous and could result in death.”

Causes of Malnutrition in Horses

A horse might need a refeeding protocol for a variety of reasons. “Inadequate calorie intake over a prolonged period, or the total absence of calories over a short period of time, can set the stage,” says Williams. Dental disease, chronic illnesses such as pituitary pars intermedia dysfunction (PPID, previously known as equine Cushing’s disease), severe asthma, chronic pain, internal abscesses, or pneumonia can also cause malnutrition in horses, she adds.

When to Implement Refeeding in Horses

Owners and caretakers managing a severely underfed horse must understand the concept of refeeding and the importance of gradually increasing feed, says Williams—not introducing large amounts of food quickly, which might be tempting when faced with a skinny horse.

“When to follow a refeeding protocol depends on the unique situation,” says Williams. “Both the body condition of the horse and what they have been consuming should be taken into consideration.” Williams said most horses at a BCS of 3 or below will likely need a refeeding protocol.

Veterinary Oversight When Refeeding Horses

Veterinarians provide critical oversight during the refeeding process, monitoring health status and addressing any underlying issues contributing to the horse’s malnourished state. “We normally want to check a biochemistry profile that includes electrolytes as well as kidney values,” says Whalen. “A dental exam is important, as well as a fecal sample to evaluate parasite load.”

Keep in mind a horse may not be stable enough to undergo dental exams and floating at the very beginning of the rehab process, she adds.

Because it can take a few days for electrolyte imbalances to occur when refeeding horses, initial bloodwork might not show abnormalities. Veterinarians should regularly recheck bloodwork during the first weeks, she adds.

During the refeeding period caretakers should monitor the horse closely. “Watch the animal’s energy level and demeanor for weakness or decline,” says Whalen. “Monitor for signs of gastrointestinal upset such as diarrhea and colic. Track water intake and manure output closely.”

Any concerning changes might indicate a setback in the refeeding process and should prompt immediate veterinary attention.

Refeeding Protocol in Horses

Refeeding protocols prioritize high-nutrient feeds provided in small quantities. “The focus is not that you’re feeding poor-quality feed products,” says Williams. Rather, “you’re feeding high nutrient value but just limiting the amount as to not have massive blood insulin rises So, things like alfalfa are okay, but it must be limited.

For the horses with dental issue, feeding small amounts of soaked forage products, such as alfalfa cubes or beet pulp mashes, can help.

The refeeding protocol veterinarians commonly follow was published by Carolyn Stull, PhD, and Christine Witham, DVM, in 1998. It includes:

• Days 1–3: Feed 50% of total energy needs over six meals (one meal every four hours).
• Days 4–5: Feed 75% of total energy needs over four meals (one every six hours).
• Days 6–10: Feed 100% of total energy needs over four meals (one every six hours).
• Days 10–30: Feed 100% of total energy needs with free-choice hay, replenished every eight hours.
• After Day 30: Once the horse reaches ideal body weight, continue free-choice hay, replenished twice daily.

Selecting feeds with a low glycemic index avoids spikes in blood glucose and insulin. “We say glycemic index, which means low-starch feeds,” says Williams. “Something with more digestible fibers in it is what we are looking for. Beet pulp is a rapidly fermentable fiber and without molasses it can be a good choice as it has a low glycemic index.”

Take-Home Message

Horses recovering from neglect or medical conditions causing loss of body condition often need a structured refeeding program. This involves using high-quality forage in small amounts, which supports healthy weight gain while minimizing the risk of refeeding syndrome. Owners should partner with a veterinarian to ensure safe, effective rehabilitation of starved horses during refeeding.

Editor’s Note: Feeding schedule adapted from: Witham CL, Stull CL. Metabolic responses of chronically starved horses to refeeding with three isoenergetic diets. J Am Vet Med Assoc. 1998;212(5):691–696.