Horses are often fed diets that also contain high levels of grains and supplements to maximise growth or productivity. Katie Young, PhD, consulting equine nutritionist for Purina Mills, presented information on forage options for horses with commonly encountered special needs, including recurrent airway obstruction (RAO) or chronic laminitis, at the Purina Equine Veterinary Conference.

Horses with RAO (also known as heaves) have a hypersensitivity to airborne allergens from hay, feed, or bedding, or pollens in summer pasture. Young recommended immersing hay in water so it is completely wet before feeding it to RAO horses. This quick dunk is as efficient in diminishing dust and mold as soaking would be, but it does not leach out nutrients. Avoid feeding from hay bunks or round bales that encourage horses to burrow their heads into hay and, thus, repeatedly expose them to the allergens.

Straight grains, such as rolled oats, can be twice as dusty as hay and might also need wetting. Owners can replace hay and grains with pelleted complete feeds to significantly decrease particulates from the diet that the horse could breathe in.

Young stressed that management strategies are critical for success with RAO horses--house these horses outside, or at least ensure excellent barn ventilation so the horse has an adequate supply of fresh air. Anything that increases dust concentration in shared airspace is problematic, so remove horses from the barn when mucking, stripping, or bedding a stall, or when distributing hay, even in adjacent stalls. For a horse with summer pasture-associated obstructive pulmonary disease, keep pasture short or keep the horse off pasture until winter.

Another special needs dietary strategy Young discussed is managing laminitis. While low-quality forage might be appealingly low in soluble carbohydrates, it might supply only marginal amounts of amino acids, copper, and zinc, which are necessary for hoof health and healing. Warm season grasses (bluestem, Bermuda, and prairiegrass) are better hay sources for laminitic horses--they store sugars as starch rather than fructans and tend to be lower in soluble carbohydrates (read more on this).

Alfalfa is low in sugar and starch, but excess calories make alfalfa inappropriate for overweight laminitic horses. Cool-season grasses (brome, rye, and orchard grass) store high sugar concentrations. Soaking hay for 30 minutes in hot water or an hour in cold water (and discarding the water before feeding) removes some soluble carbohydrates, she said, but this technique might necessitate the supplementation of other nutrients also leached from hay during the process. You can have your hay analyzed at qualified labs.

Young urged horse owners to consult their veterinarian or equine nutritionist to obtain applicable data for assessing whether they should modify their horse's diet.

Read more from the Purina Equine Veterinary Conference. This meeting was held Oct. 17-19 in St. Louis, Mo.

About the Author

Nancy S. Loving, DVM

Nancy S. Loving, DVM, owns Loving Equine Clinic in Boulder, Colorado, and has a special interest in managing the care of sport horses. Her book, All Horse Systems Go, is a comprehensive veterinary care and conditioning resource in full color that covers all facets of horse care. She has also authored the books Go the Distance as a resource for endurance horse owners, Conformation and Performance, and First Aid for Horse and Rider in addition to many veterinary articles for both horse owner and professional audiences.

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