Other nutrition-related factors
The NRC notes that "specific, objective information regarding nutritional management of horses with chronic laminitis is not
available."2 However, it might be best when feeding such horses to minimize energy intake and prevent excess body weight in order to
minimize mechanical stress on the foot. To provide nutrients necessary for hoof growth and repair, rations should be of proper
nutritional plane, have high-protein quality and include a complete balance of required micronutrients such as biotin.
Out of concern for the development of obesity and laminitis, it is prudent to encourage owners to provide regular exercise,
monitor body weight (BCS) and maintain animals at an optimal weight (BCS 4 to 6 on a 9-point scale).
Although obesity and mechanical trauma due to increased weight load may be related to the development of laminitis, it is
possible that the risk in obese horses or ponies (BCS > 7) is more appropriately attributed to the development of insulin
resistance or equine metabolic syndrome.
"From my personal perspective, there is a lot of misinformation out there that I think is detrimental to the horse," Hood
says. "The concept that you have to take weight off horses because their front feet hurt, and if you take weight off, they
hurt less, is not quite valid because these horses need to grow their feet and need lots of protein and lipids to do so. If
you cut back their diets, you're potentially going to have a detrimental effect. It's obvious if you're overfeeding, a horse
can get into a laminitis problem that really impacts the disease. But there is very little data as to exactly how specific
nutrients or supplements can affect the horse. If you overfeed on corn or energy, you put the horse at risk, but the mechanism
by which that works is unknown."
"As for chronic laminitis, you're really just trying to prevent another episode," says Siciliano. "You're trying to keep affected
horses from being overconditioned and overfed. Know what their digestible energy requirements are and provide them. Just practice
good feeding management, making sure what you're feeding them is balanced, with adequate micronutrients to help stimulate
hoof growth. Probably equally important — maybe more important — is the farrier and the environment that owners keep their
horses in. Ensure that the horses are in a good environment for their feet and have proper trimming, shoeing and hoof care.
That's going to have equal or even more impact on their condition than what they're being fed."
For a horse with chronic laminitis or one prone to laminitis, "we don't really stress the energy portion as much as we do
the sugars and the starches in the diet," says Carey Williams, PhD, Equine Science Center, Rutgers University. "We really
stress keeping them on a low-starch diet by using more poor-quality hay. If they need extra calories, which most of them don't,
then it needs to be a low-starch, low-carb feed. If the horse feels good enough to be exercising and needs more energy to
maintain body weight, then we recommend using fat to increase the energy content of the diet. Overfeeding is an issue, but
if you have a horse that needs the energy, we recommend not to add the calories from carbohydrates or sugars; it needs to
come from a different source."
"As far as nutrition goes, one thing we've got going on is looking at the basic nutritional requirements of the equine hoof
— its physiologic aspects, what it's made up of, what it theoretically needs and how we can provide it," says Hood.
Hood is working with Josie Coverdale, PhD, a nutritionist at Texas A&M University, to determine how best to feed a chronically
foundered horse. "Although there is much information out there on how to feed a chronically foundered horse, there is very
little data," Hood says. "That will be the purpose of what we're trying to do — to determine what's wrong with the horse,
medically, and then how that affects the nutritional needs of the horse," he says. "It's a bit complex because you have horses
that are essentially normal and then those that have chronic laminitis, metabolic syndrome or pituitary pars intermedia dysfunction.
That makes each case a distinct individual — the highly stressed horse needs one nutritional protocol, while the metabolic
syndrome patient might need an entirely different one."
"I think we keep looking at triggers, not at how to maintain or even basically treat laminitic horses nutritionally," says
Coverdale. "We're convinced there are some protein aspects at play — not just crude protein-related, but possibly an amino
acid imbalance or a greater requirement. Whether it's sulfur-containing amino acids or branched-chain amino acids, I'm not
sure. I can't imagine that laminitis-affected horses have the same amino acid requirements as a healthy horse at maintenance."
"We don't even honestly know the limiting amino acids for maintenance or for growth, so for laminitis we're starting from
scratch," Coverdale says. Most cereal grains are either limiting or marginal in methionine. "I've done some methionine work
for growth in weanlings, and we've not been able to limit growth with normal cereal grains available to us or to make a methionine-deficient
diet. Although it is difficult to produce such a diet, whether there is a benefit of super-supplementation of amino acid-containing
products is not known."
Research into this common debilitating equine disease is ongoing. Veterinary practitioners should consider an individualized
and, in many cases, multifactorial approach to prevention and management of laminitis.
Ed Kane, PhD, 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.
1. USDA. Lameness & Laminitis in U.S. Horses. USDA: APHIS:VS, CEAH, National Animal Health Monitoring System, April 2000.
2. National Research Council. Nutrient requirements of horses. 6th ed. Washington, D.C.: National Academies Press, 2007.
3. Harris P, Bailey SR, Elliott J, et al. Countermeasures for pasture-associated laminitis in ponies and horses. J Nutr 2008;136:2114S-2121S.