Nutritional Support for Injured Equine Athletes
By Erica Larson, News Editor • May 29, 2012 • Article #29188
Photo: Anne M. Eberhardt/The Horse
Editor's note: This article is part of TheHorse.com's ongoing coverage of topics presented at the 2012 Alltech Symposium, held May 21-23 in Lexington, Ky.
When a performance horse is injured, his show schedule or exercise regimen shouldn't be the only facets of his life that change. As one equine nutritionist explained at a recent symposium, an injured horse's diet can either help or hinder the healing process, and might need to be adjusted from his performance diet.
During a presentation at the 2012 Alltech Symposium, Tania Cubitt, PhD, of Performance Horse Nutrition, explained that even though injured horses necessitate stall rest or minimal exercise, they could be in greater need of some dietary components than during training.
"The horses are used to a very structured routine," Cubitt relayed, referencing strict feeding schedules, regular exercise, and/or set turnout time. "(Upon injury) it's totally different."
Once the veterinarian tends to an injury, she said, the horse generally returns to the farm, stops training, and goes on stall rest with limited or no turnout, as prescribed by the veterinarian.
Metabolic Consequences of Injury
An injured horse's appetite often decreases due to pain, stress, inflammation, or a combination of the three. The problem with this, as Cubitt explained, is the horse's body has an increased energy demand to fuel healing. So without dietary adjustments the animal often enters a catabolic state, which she described as the break down and use of body tissues to provide energy for healing.
"The body uses energy to fuel the healing process, and the body's stored protein becomes a source of energy," she said. "Then the horse becomes weak due to protein loss," which slows the healing process.
Thus, it's important to understand what nutrient needs must be fulfilled when nursing an injured horse back to health.
Nutrient Use and Needs
Ninety percent of the calories healthy horses use daily come from fat stores within the body, Cubitt said. Conversely in injured horses, only about 50% of the calories used come from stored body fat, she relayed. The injured horse gets the rest of his energy from stored carbohydrates (about 20%) and the breakdown of body tissue (about 30%).
Thus, to keep a healthy body condition and help the healing process, the injured horse has elevated requirements for both protein and energy, Cubitt said. Additionally, their trace mineral and vitamin requirements could increase as well.
Cubitt relayed that there are no published guidelines for a sick or injured horse's energy needs. However, using information published on the energy requirements of sick and injured humans, Cubitt estimates an injured horse probably requires 18-22 megacalories per day (for reference, a horse on a maintenance diet requires 15-16 megacalories per day, according to the National Research Council).
Injured horses also have increased protein requirements compared to horses at maintenance, Cubitt said. She cited research that found injured horses have similar protein requirements as horses in light work, so she suggested using that as a guideline when evaluating protein requirements.
Additionally, Cubitt said, injured horses' copper, zinc, and selenium requirements increase, as well as their omega-3 fatty acid requirements. There are no set requirements for omega 3 fatty acids; however, based on their anti-inflammatory and immune boosting functions increasing them in the injured horses' diet could be beneficial, she said.
Feeding Injured Athletes
Cubitt suggested maintaining injured horses' body condition score at 5 to 5½. She stressed not to keep them too light, as thin horses tend to heal slower than horses of moderate body condition.
She suggested decreasing the sugar and starch concentrations in the horse's diet while increasing fat and fiber to ensure he consumes enough calories without taking in energy sources that could lead to excitable behavior (increasing risk of further or reinjury).
Avoid cereal grains, but embrace alternative forages like beet pulp, constant access to hay, and top-dressed oil to meet horses' energy requirements, she relayed.
Because injured horses will feed upon their body's protein store to maintain the healing process, Cubitt stressed that providing these animals with adequate protein is critical. Alfalfa hay, ration balancer pellets, and soybean meal (which is found in many commercial concentrates) are all good sources of protein, she said. Cubitt reminded attendees that protein will not "make the horse go crazy," so owners and managers shouldn't worry about that aspect of feeding protein to their animals.
Cubitt also cautioned that managers should ensure their injured performance horse is consuming adequate micronutrients, as these are crucial to helping the body heal. She recommended feeding 1 to 1½ pounds of ration balancer pellets daily to keep the horse's micronutrient level satisfactory.
Additionally, Cubitt recommended discussing the possibility of light, limited exercise with the veterinarian to help the horse keep his muscle tone. Limited turnout in a small paddock, hand walking, swimming , and stints in a walking machine could all help the horse retain muscle tone during layup, she said.
Altered nutritional needs are just one facet of managing an injured performance horse, but it's also one of the most important aspects. Being nutritionally prepared when a patient arrives home with an injury will help him on the road to recovery.
"The horse is designed to stay alive, so they will do whatever it takes to get better," Cubitt concluded. "We need to be ahead of the curve to ensure they won't rapidly break down their own tissues and organs and supply quality nutrients to aid in a speedy recovery."