Rotating Article

for: Week of December 3, 2001

by: John D. Atkins

Extension Agronomy/Livestock Agent

Santa Rosa County

"Selecting Hay for Horses"

Many horse owners select hay for their horses based on what they think looks good or on what they have been told is good. Opinions vary all the way from believing that Bermuda is an essential part of every horse ration to those who insist on alfalfa for all horses. Forage should be the foundation of every horse ration. The quality of that forage, the composition of the hay, and the way the hay is delivered to the horse are all fundamental for good horse feeding. This article’s goal is to help you develop a healthy ration based on quality forages.

Horses are herbivores, animals made to live primarily on plants (forages). About 65 percent of the digestive capacity of the horse is in the lower gut, or the cecum and colon. The cecum and colon contain large microbial populations which allow for the digestion of fibrous feeds, much like the digestive tracts of cattle and sheep (ruminants). Evidenced by the size of the lower gut and the presence of bacteria, the horse is designed to digest primarily forages. Horses have fewer digestive upsets and behavioral vices such as wood chewing and cribbing, when hay is the main portion of the ration.

For proper digestive tract function, horses require a minimum of 1 percent of their body weight per day in long-stem dry matter. This can be done in any form that is convenient and economical. When the total ration particle size is below .5 inch in size, problems with rate of passage, digestibility and behavioral vices occur.

Forage quality is an expression of the characteristics affecting consumption and nutritive value, which contribute to a horse’s health and performance. Even though many factors affect forage quality, no single factor, including color, can be used to make predictions. Maturity stage at harvest, forage species and variety, leafiness, harvest and storage conditions, and the presence of foreign objects, weeds and pests are all important factors affecting quality. A closer examination helps the horse manager economically select the best hay for his or her situation.

Plant maturity is visually determined by the amount of seed heads of grasses or the flowers of legumes present at the time of harvest. Forages in the vegetative stage will not have visible seedheads or flowers. As plants progress through seedhead or flower bud emergence, pollination and seed formation, the concentration of structural carbohydrates and lignin increases and crude protein decreases. The structural carbohydrates, cellulose and hemicellulose are partially digested by the bacteria in the horse’s lower gut, but lignin, another component of plant fiber, is not digested at all. As lignin increases 1 percent, the digestibility of the forage dry matter decreases 3 or 4 percent.

Leaves contain more nonstructural (digestible) carbohydrates and protein than stems. Nonstructural carbohydrates, which include plant sugars and starches, are highly digestible. When forage plants mature, the leaf to stem ratio decreases. Hay baled at ideal moisture levels (17 to 20 percent) has more leaves because fewer shatter and fall off than when the forage is baled too dry. But baled too wet, hay will become moldy. Leaf diseases can also cause premature leaf drop and reduce the leaf to stem ratio, reducing nutritive value. Forages with greater amounts of leaves are higher in quality.

Hay also should be inspected for the presence of other foreign matter, such as wire or nails, and the presence of dusts and molds. A musty odor indicates that the hay was put up too moist which allowed molds to grow. Horses are especially sensitive to dust and molds and they can result in respiratory problems as well as potential colics.

John Atkins is Agronomy/Livestock Agent for Santa Rosa County.

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