Dr. Kimberly Brokaw, DVM
(8/2015) This time of year, hay is on the mind of a lot of farmers and horse owners. Horses usually consume 1-2% of their body weight each day in hay, if grass or other forage is not available to them. If a horse is boarded, the barn usually provides the hay. Owners are then often unaware of what
goes into having good hay for their horses. There are many different types of hay, cuts of hay, and quality characteristics of hay. Since dairy cows, beef cows, horses, sheep, goats, alpacas, each do best with different types of hay, I will be discussing hay for horses. Even among horses there are different qualities and types that different horses will do better on. A nice,
tasty, second cut alfalfa blend may be ideal for a performance horse, but could contribute to disease and permanent lameness in an already fat and laminitis prone pony.
There are many different types of grasses that can be used to make horse hay. Hay is divided into two categories, grass and legume. Timothy and orchard grass are your more commonly fed grass hays in this part of the country. Alfalfa and clover are your more common legumes. Legumes tend to be richer in nutrients and supply more energy than grass hays.
Alfalfa is an excellent source of calcium, protein, and energy. Grass hays tend to be lower in calcium and protein and provide more fiber than legumes. The quality and nutritional value of the hay also changes based on stage at which it was cut and baling conditions. Many times, horse owners consider a mixture of legume hay and grass hay to be the perfect hay for a
performance horse. Unfortunately, that perfect mixture can be hard to obtain.
Regardless of which type of hay you pick for your horse, it should be good quality. There are 5 main factors you should look at when evaluating hay; stage of maturity, leafiness, color, foreign material, odor and condition.
The stage of maturity when the hay is cut relates most to nutrient quality. Over mature hay tends to be fewer nutrients dense, higher in fiber, and less palatable. In Maryland, most hay should be first cut prior to mid- June. After that it tends to get over mature and loose nutritional value. Second and third cut hays are nutrient dense and often
contain fewer weeds. Horses tend to prefer second and third cutting hay but these hays can lead to overeating in an already plump horse or fat pony.
The leafiness of hay usually relates to stage of maturity at baling. Younger plants have more leaf and fewer stems. The leaf is more nutrient dense and the stem has higher fiber. As the grass matures, it's stem content increases. Alfalfa leaf content can also relate to how it was handled during baling. The leaf can fall off the plant during baling if
it is allowed to get too dry, if it is overly mature when cut, or if it gets rained on after being cut and needs to re-dry. Leafy hay tends to have more nutritional value than hay with fewer leaves. Some horses need the extra nutritional value in leafy hay, and others are best off with lower calorie hay.
While most people want to purchase beautiful green hay, color is not always a good indicator of quality. Instead it tends to indicate how it was cured. Green hay was likely cut at the ideal maturity and cured rapidly. Yellow hay is usually the result of sun bleaching. If the hay is yellow throughout the bale, it was bleached on the field. If just the
outside parts are yellow, then it was exposed to sunlight after being baled. Some barns will store their hay in the dark with blinds on the windows to try and keep the hay from turning yellow even though it minimally effects the nutritional value. Brown or black hay is usually the result of getting rained on or molding It also usually has a musty odor. This hay should not be
fed to horses.
Foreign material such as weeds and dead animals should not be found in hay. While some weeds such as poison ivy are more a bother for the owner rather than the horse, other weeds are toxic. Nightshades, cherry leaves, and other plants can be toxic if the horse is given too much. When dead animal are baled into the hay, not only is it gross, but can be
fatal as well. The horse usually avoids eating the carcass, however botulism can be found in the hay and lead to toxicity and death.
When evaluating for odor and condition of the hay the main thing to look for is mold and dust. Hay that smells musty or rotten is contaminated with mold. The presence of dust and mold relates to how the hay was baled. Hay that is baled wet will mold and get dusty. Mold can cause a variety of problems for your horse. Just a little mold can trigger
respiratory issues and diarrhea while very moldy bales can cause colic and death.
There is a difference between baling wet hay and having hay get rained on. This year it has been a very wet year and it has been difficult to get a long enough period of time to properly cut, dry, and bale hay. If the hay is going to get rained on, it is best that it be rained on shortly after being cut and before it has had time to dry. Nutritional
losses to the hay are greatest if the hay is allowed to dry and partially cure and then gets rained on for several days. However, hay that is cut and then gets a short but intense rainfall prior to curing has less nutrient loss. Either way the hay should then be allowed to properly dry and cure before being baled. Some fat ponies, or horses with Cushings disease might
actually benefit from eating rained on hay. Frequently I advise clients with insulin resistant and Cushings horses to soak their horses hay before feeding it. Rain can also serve the same purpose in that it washes out some of the soluble sugars without burdening the owner with the cumbersome task of having to soak the hay prior to feeding it.
Visual evaluation of hay can give you an idea of its quality. However, the only true way to know the quality and nutrient content of your hay is to have it tested. There are numerous places that provide testing services at a relatively inexpensive rate. Some hay farmers routinely send their hay off to be tested for nutritional value. This is
particularly important if the horses who will be eating this hay have metabolic problems or Cushings syndrome that make it best that they avoid hay that is high in carbohydrates.
Moisture can be an enemy of good hay. There are many stories of horse owners buying a barn full of lovely, green, freshly made hay, only to discover that their barn is in flames a few days later. Hay that is baled and put in the barn while moist can heat up and explode into flames. Many hay farms test their hay with a moisture meter. If the moisture
level is high, they treat the hay with salt or propionic acid before baling to dry the hay. Barn fires do not make for happy hay customers. If wet hay doesn't heat up and burst into flames, hay that is baled while too wet often molds a few weeks after it is baled. It is frustrating for a horse owner to buy what looks to be lovely hay, only to find that the hay is full of mold
a few weeks later.
Farmers who make good hay deserve a lot of appreciation and respect. While good weather plays a role in making that nice green bale of hay with soft stems, lots of leaves, and a lovely smell, there is also a lot of work and knowledge that goes into making that bale.
Read other articles by Dr. Kim Brokaw