Formulated horse feed. Most horse feed incorporates soy bean meal as main protein source

Why Soy Products Are Not Only Safe, Horse Feed Staples, They Are A Protein Mainstay.

Horses at different physiological states have varying protein requirements dependent also on performance level and must consume a specific amount of protein on a daily basis to remain healthy. Protein, comprised of the essential amino acids or the building blocks for new cell growth, is required for maintaining all normal body functions in a horse. Most horses feeds incorporate soy bean meal as the mains source of protein in formulated feeds. Soy has long been the gold standard and most complimentary source of protein for the horse.

Horses should be provided with only vegetarian sources of protein in their horse feed to supply amino acids. Soy protein provides the closest match to equine amino acid requirements. Recently, some have begun to question how much soy can be safely consumed to gain health benefits but not risks. The claimed benefits of soy include reduced risk of cardiovascular disease; osteoporosis, breast and prostate cancer whereas potential adverse effects include impaired thyroid function, disruption of sex hormone levels, changes in reproductive function and increased breast cancer risk. Many of the human soy-related problems reported in the news are coming from women or infants who over consume soy protein or from people who are truly allergic to soy products.

Because horses are strict herbivores, they can have completely different metabolic responses to digesting individual ingredients than omnivorous humans do, so the effect of these ingredients in horse feed are different. No research data currently exists that shows soy protein has a negative effect on horses when it's fed in reasonable amounts, such as those included in nutritionally balanced horse feeds.

Whether you choose to use soy products or not, equine nutritionist Dr. Amy M Gill advises working with a reputable company or manufacturer. "Use a pre-formulated, balanced horse feed suited for the physiologic needs of your horse," she said. "Provide adequate forage and fresh water. And, be sure you're following the manufacturer's recommendations for feeding."

If your horse exhibits physiological or behavioral changes and you suspect a dietary cause, Gill recommends testing before leaping to any conclusions. "Anytime there is a significant and/or dramatic change in a horse, always consult with your veterinarian," she advised. "At a minimum, run blood tests, including a complete blood count (CBC) and chemistry panel, to eliminate any physical issues, including ulcers.”