What the Hay?

Here’s what you need to know about this important forage in your horse’s diet.
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What the Hay?
Not all hays are created equal—some are better for your horse’s health than others. | Photo: Photos.com

Everything you need to know about this important forage in your horse’s diet

Selecting hay for your horses is never as simple as calling up the farmer down the road and having him drop off a truckload of whatever he’s harvested. Indeed, not all hays are created equal—some are better for your horse’s health than others. In this article we will provide an overview of the types of hay commonly fed to horses and how to select good-quality hay.

Types of Hay

Hay can be categorized as one of three types: grass, legume, or cereal grain. Grass hays have fine stems, long leaves, and sometimes seedheads. They can be subdivided into two groups: cool-season (those that grow best at 60-80°F) and warm-season (those that grow best at 85-95°F). Examples of perennial cool-season grasses include timothy, orchardgrass, smooth bromegrass, fescue, and bluegrass. Warm-season grasses include Bermuda and bahiagrass.

Legume hays tend to have coarser stems than grass, and examples of these forages include alfalfa and clover. Producers commonly mix alfalfa hay with other grasses for better yield.  

Free Download: Your Guide to Horse Hay

Cereal grain hays are made from the leaves and stems of plants such as oat and wheat. They are fed to horses less frequently than other hays, due to their low nutrient levels, but if they’re harvested before maturity (at maturity they’re considered straw) these forages can offer nutritive value.

Farmers typically harvest cool-season grasses two to three times per year. Warm-season grass hay can be harvested three to four times per year. Legumes can be harvested three to four times per year in the Midwest and up to 12 times per year in Arizona and California. Each harvest is referred to as a “cutting,” and location, weather, and rainfall greatly influence the number of cuttings.  

Producers bale hay in either square or round form. Round-baled hay, which is usually stored outside, can present a number of problems for horse owners if they store it improperly or do not offer it in a feeder. If you don’t have enough horses to consume a round bale within about a week, for instance, the amount of hay waste increases, as does the potential for mold growth in rainy and warm weather. Horse owners commonly feed square bales, which are easier to handle and store than round bales but tend to be more expensive.

Nutritional Characteristics

The main nutritional differences between grass and legume hays lie in their crude protein, calcium, nonstructural carbohydrate (NSC), and digestible energy levels. Protein is important for most all vital processes, and horses get much of their protein from forage. Grass hays contain 4-12% crude protein, while legumes contain upward of 15-20% crude protein. When compared with grass hays, legumes are typically higher in digestible energy, which is needed to fuel all basic body functions. They also contain calcium, which maintains normal brain and nerve function and aids in heart, skeletal muscle, and intestinal contraction, and lower amount of NSCs, which are undesirable in large amounts because they contribute to exaggerated insulin responses and diseases such as laminitis.   

Regional Availability

Your hay options depend on where you live, as some varieties are more prevalent in particular regions. “Legumes are common throughout the United States; perennial cool-season grasses tend to be grown in the upper two-thirds of the U.S. (coast to coast); and warm-season grasses tend to be located in the lower third of the U.S. (central and eastern),” says Krishona Martinson, PhD, equine extension specialist in the University of Minnesota’s department of animal science, in Saint Paul. “Cereal grain hay is mostly confined to the West and the Midwest to some degree.”

Hay Selection

Karen Davison, PhD, nutritionist with Purina Animal Nutrition LLC, says the most important factor to consider when selecting hay is quality, which depends primarily on its stage of maturity at cutting. Rainfall, irrigation, fertilization, weather, hay handling during harvest, and storage conditions also contribute to a hay’s quality. Good-quality hay appears green and leafy; it’s soft and pliable to the touch; has few seed or flower heads; smells pleasant; and is free of mold, dust, or weeds.

Davison says a hay’s condition and maturity also significantly affect its digestibility. Sometimes the very characteristics that help us recognize a hay actually penalize it. For instance, though horse owners often identify timothy hay by its seedheads, the presence of seedheads (or flowers in the case of legumes) indicates the hay was cut at a later stage of maturity and, hence, is of lower quality.  

Another misconception about hay involves the superiority of one type over another. “Any hay, anywhere, can be good or bad,” says Davison. For instance, early maturity timothy hay could be more nutritious than your average Bermuda grass hay, whereas seedhead-riddled timothy might be less.

Martinson recommends matching hay quality to your horses’ life stage and activity level. Timothy or alfalfa with seedheads or flowers might meet the basic nutrient needs of a mature horse that is not active or breeding. Growing, breeding, or active horses typically require higher-quality, less-mature hay.  

Hay should contain less than 10% nontoxic weeds and zero toxic ones. Extension agents can help you identify weeds and regional toxic plants to look out for.

We know green is important, but Martinson says not to “get hung up on color” when choosing hay. “A lighter color means it was exposed to sunlight or rain, and some of the vitamins and minerals have leached out. Even the best-quality hay is lacking in some vitamins and minerals, and a horse eating 100% of its diet in hay should be fed a ration balancer,” which provides the additional vitamins and minerals that hay lacks.

Certain laboratories can analyze hay’s nutritive content, but the results can be challenging for the average horse owner to attain and interpret. Proper preparation of hay for analysis involves sampling many bales with a hay probe, as nutritive content can vary greatly between cuttings and fields. “There is very little value in sending a flake or a handful of hay to a lab,” says Davison. She suggests relying on your visual appraisal of the hay and your horses’ consumption of it as a means of assessment unless buying six months to a year’s supply at a time or feeding a horse with special needs.  

Is a Probe Necessary to Test Horse Hay?
RELATED CONTENT: How to Sample Hay for Analysis

If you’re buying in large quantities and have the appropriate sampling equipment, Davison suggests testing hay for at least digestible energy, crude protein, acid detergent fiber (ADF), and neutral detergent fiber (NDF). Owners of horses sensitive to dietary carbohydrates (e.g., horses that are insulin-resistant, predisposed to laminitis, or have equine metabolic syndrome) might also want to test for starch and water soluble carbohydrates (WSC) and avoid hay that is high in nonstructural carbohydrates (add starch and WSC together to estimate NSC content).  

A word of caution when it comes to hay selection: Droughts, flooding, wildfires, snow, freezes, and unfavorable temperatures have plagued production and driven up hay demand in the United States. In addition, the cost of fertilizer, fuel, hay, grains, ingredients, and almost every other input in the horse industry has increased, so take care to find and purchase the best hay you can afford. After all, hay’s calories and other nutrients should make up at least 75% of a horse’s diet. Attempting to save money by buying poor-quality hay is one of the costliest mistakes a horse owner can make, and it will be paid for in lost weight and condition and nutrition-related illnesses.  

How to Purchase Hay

Generally, you can purchase hay from feed stores or hay growers. Be educated about the hay you’re feeding your horse, says Martinson, and avoid any surprises by asking the following questions when buying hay: What is the average weight of the bales? At what maturity was the hay cut? What type or mix of hay is it? Where was the hay harvested from? Was the hay rained on after being cut? How was the hay stored? Was the hay fertilized and sprayed for toxic weeds? What is the price per bale (or ton, depending on how much you’re buying)? How will the hay will be loaded or delivered?

How to Store Hay

Martinson suggests storing forage where it will be protected from the elements, such as in a three-sided hay shed. Make sure the roof is waterproof, and try to minimize access to the area by mice, rats, and other animals. Do not stack hay that’s been baled wet directly on the ground; use pallets to allow air circulation. Stack the hay in such a way that a minimum amount of surface area is exposed to the environment.

Take-Home Message

Above all else, select your horse’s hay based on quality. Forage species, weather, and agronomic practices such as fertilizing impact hay quality, but maturity at which the hay is cut is the greatest determinant. A forage test and visual appraisal of the hay and your horses’ consumption of it are practical methods of determining quality. Your selection will depend on the local supply and your horses’ nutrient requirements.

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Written by:

Jon Padgham is a freelance writer and works as an equine nutritionist for D&L Farm and Home in Aubrey, Texas. He obtained his master’s degree in horse nutrition from Kansas State University in 2001.

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