I have been a strong proponent of the role of nutrition in health and optimal function for four decades but with the understanding that while it is pivotal it’s not the sole answer to everything. Scientifically unrealistic claims for the benefits of supplements mislead owners/caretakers and end up eroding confidence in the power of nutrition.
No silver bullet supplements can guarantee safe grazing for all horses.
Some things are straightforward. Pregnant mares with severe selenium deficiency can give birth to foals with white muscle disease. Supplement those mares with adequate selenium when pregnant and this doesn’t happen. It’s rarely that simple.
For example, there’s been a mini proliferation of “topline”/muscle supplements lately. They typically are 30 to 60% protein and deliver essential amino acids (the building blocks of protein) in dosages ranging from miniscule to sufficient to correct a deficiency state in some circumstances.
The problem is you cannot build muscle just by feeding protein unless there is a dietary deficiency, and there certainly is no supplement that can specifically target the topline. There are several potential causes of topline wasting that cannot be fixed with protein. These include aging, Cushing’s Disease, chronic lung disease, poor saddle fit, Equine Motor Neuron Disease, EPM and Equine Polysaccharide Storage Myopathy.
The back and croup are also normally covered by a thick layer of fat. Weight/fat loss alone will cause lack of definition along the topline. The other key “ingredient” to building muscle bulk in any location is exercise.
Then there is the persistent myth that there is a widespread issue with hindgut acidity and hind gut ulcers, with a corresponding assortment of supplements that claim to address it. The pH of the hindgut normally varies with diet – highest with hays, lower with pasture and hay/grain diets.
There is not one shred of credible evidence showing these normal variations cause ulcers, pain or behavioral and gait issues. The most recent study that set out to investigate colonic ulcers and causes found ulceration in 12 of 56 (21%), 9 of which were clearly caused by parasites. Only 3 horses (5%) had colonic ulcerations with no clear cause visible but the health and drug (phenylbutazone) history of those horses was not known. http://onlinelibrary.wiley.com/doi/10.1111/evj.24_12732/full
Worse yet are claims for supplements that will let you put any horse out on spring pastures without having to worry about laminitis. Pasture-associated laminitis is caused by higher starch and simple sugar levels in the new growths of grass. Supplement ingredients that address hindgut fermentation (e.g. hops) are irrelevant. Ingredients supporting blood sugar control in humans are also useless since insulin is the problem, not high blood sugar.
It’s true that mineral nutrition is important to the health of hyperinsulinemic horses, but there is no evidence that mineral deficiencies can actually cause hyperinsulinemia or that correcting those deficiencies or megadosing minerals alone can protect from high insulin levels and laminitis. Please don’t be fooled. The only way to protect horses prone to hyperinsulinemia from pasture associated laminitis in the spring is to keep them off the pasture.
It’s human nature to want a quick fix, a simple solution to make everything normal. Unfortunately, that’s rarely possible. Nutrition and appropriate supplementation is just one piece of the puzzle. Silver bullets are for werewolves.
Eleanor Kellon, VMD