How Well Do You Know Your Hay? Hay analysis is the foundation of your feeding plan
By Dr. Juliet M. Getty
You’ve just bucked a couple of month’s supply of hay into your barn—or maybe an entire season’s worth—and now it’s time to get acquainted with it. You made sure it was green and attractive, fresh-smelling and free of mold. You’ve stored it under cover and away from the incursion of any damaging moisture. Now you’re ready to find out what it offers your horse in the way of nutritional value.
Keep in mind that when you take fresh healthy pasture and you cut it, dry it, and store it to make hay, it loses most of its vitamin content as well as its omega 3s and omega 6s fatty acids. It no longer has vitamins E, C, D or beta carotene (which is used to make vitamin A). Therefore, if the horse is getting predominantly hay and is not getting a commercial feed fed according to directions, then you really need to supplement the diet with a good vitamin/mineral supplement. But you’ll want to know what’s in your hay before you start making up for what’s not.
Hay analysis gives you the starting point from which to evaluate and balance your horse’s whole diet. If you purchase at least two or more months’ worth of hay at a time, it is worth having it analyzed. Your local county extension service may offer analysis services, or consider sending a sample to Equi-Analytical Laboratories (www.equi-analytical.com). Follow their directions for selecting and submitting samples.
What does the hay analysis tell you? Typically, it will return the following information:
Crude protein (CP)—an estimation of total protein based on the amount of nitrogen in the hay. It does not tell you anything about the amino acid composition or the protein quality. To create a high quality protein, one that will help your horse maintain and repair tissue, combine a grass hay with a lesser amount of a legume (typically alfalfa). Most grass hay contains 8 to 10% CP whereas legumes (e.g., alfalfa, clover, perennial peanut) can range from 17-20%. Grain hays (oat, rye) generally have a lower CP than grass hay.
Acid detergent fiber (ADF) and Neutral Detergent fiber (NDF)—both measure fibers (there are 5 types). Since fibers are digested by the microbes living in the hindgut (cecum and large colon), a healthy microbial population is important to allow your horse to derive calories from fiber. However, there is one type of fiber that is indigestible—lignin; the lignin ends up as manure. Lignin content increases as the plant matures. The higher these two values (ADF and NDF), the more lignin the hay contains, the less likely that your horse can thrive on this hay. The ideal ADF is less than 35%; ideal NDF is less than 45%. However, most hays have values 10 points or more higher than these desired levels. To compensate, more hay needs to be consumed. This can be easily solved by allowing your horse to have free access to hay 24 hours a day.
Non-Structural Carbohydrates (NSC)—total amount of sugar, starch, and fructan. To obtain %NSC, add together %WSC (water soluble carbohydrates) plus %Starch. If your horse needs to have a low sugar/low starch diet, the %NSC should be below12%.
Water-soluble carbohydrates (WSC)—simple sugars and fructan levels. Simple sugars are digested in the foregut and raise insulin levels. Too much can lead to laminitis because of elevated blood insulin. Fructan for the most part is digested in the hind gut, though some shorter chain fructose molecules can contribute to elevated insulin. Too much fructan generally results in laminitis caused by endotoxins in the bloodstream.
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