Horse Hays

by Frederick Harper, Extension Horse Specialist
Bill Backus, Emeritus Associate Professor
Emily Tipton, Animal Science Assistant
Animal Science Department, The University of Tennessee, Knoxville, TN

Hays to Avoid Feeding to Horses. Not all hays are recommended for horses. It is well documented that sorghum-sudangrass pastures cause serious problems for horses, including cystitis, lack of coordination and abortions. Limited information indicates that sorghum-sudangrass hay can cause similar problems; however, it should be noted that some horse owners feed sorghum-sudangrass hays.

Mares grazing endophyte-infected fescue pastures can have problems such as prolonged gestations, difficult foalings, agalactia, even foal and mare deaths. Fescue hay made from endophyte-infected meadows can cause the same problems. It is recommended to remove mares from endophyte-infected pastures and not feed endophyte-infected fescue hay after 300 days of gestation.

Additional grass hays that horses do not like or do not do well on are flaccidgrass, kleingrass and bahiagrass. Mature geldings lost weight when fed bahiagrass hay. Mature mares did not eat flaccidgrass hay as well as Coastal bermudagrass. Its dry matter and crude protein digestibility was less than bermudagrass. However, body condition score and body weight changes were similar. Flaccidgrass hay does not appear to be a good choice for young, growing horses; mares in late pregnancy; or those lactating. For the mature maintenance horse, it would seem to be okay, especially if intake needs to be limited and manure output decreased. Horses do not like kleingrass, eating only 0.29 percent of their body weight compared to 1.5 percent of bermudagrass hay. Kleingrass hay may cause liver damage.

Sweet clover hay should not be fed to horses, as it is difficult to cure without mold, which produces dicoumarol that competes with Vitamin K. This causes the horse’s blood not to clot.

Blister beetles can be a serious problem in alfalfa hay, causing horses to become sick and die. As little as eight grams of dried blister beetles can kill a mature horse. Blister beetles contain a product, cantharidin, that irritates and blisters the intestinal tract and kidneys of the horse. Horses consuming blister beetles develop colic-like symptoms in addition to depression, fever, increased heart and respiratory rates, shock, diarrhea and dehydration. If they survive 24 hours, horses urinate frequently and blood may appear in the urine. Blisters may be observed on the lips and tongue. Many horses die 48-72 hours after the onset of symptoms.

Blister beetles have been found in alfalfa hay from such states as Arizona, New Mexico, Oklahoma and Texas. Alfalfa hay cut before flowering is less likely to contain blister beetles, as is the first cutting of alfalfa hay.

A condition known as black patch on red clover causes horses to slobber. A problem only occurs if a horse slobbers excessively, resulting in an electrolyte imbalance. Horses fed red clover hay with black patch should have free-choice water and trace mineralized salt.

Short or Expensive Hay Supply. What is a horse owner to do when hay is in limited supply and/or very expensive? Drought has resulted in an extremely short supply of hay in some areas in recent years. Naturally, hay prices increase in these situations. Extremely wet weather can also negatively impact horse owners. These conditions make it difficult to make good-quality hay. Moldy hay should not be fed to horses. Horse owners have several management alternatives in these situations.

When hay is in short supply or extremely expensive, owners can first consider feeding less hay. It is not advisable to feed less than one pound of hay per 100 pounds of body weight. A 1,200-pound horse that normally gets about 24 pounds of grass hay could be fed only 12 pounds of hay. With the reduction in the amount of hay, more grain or concentrate must be fed to replace the energy, protein, minerals and vitamins lost by feeding less hay. When hay prices are high, it may be more economical to feed more grain and less hay.

In rare cases, you can limit hay intake to less than 1 percent of the horse’s bodyweight. Horse owners must be very cautious and exercise top management in these situations. It is possible to feed only ½ pound of hay per 100 pounds of body weight. However, this is not recommended except in unusual and demanding situations. It is suggested that this type management practice be of short duration until the problem is corrected, and more, better-quality and cheaper hay is available.

If this situation occurs, owners must adjust hay-feeding practices according to the type of horses. It is not advisable to limit hay intake below one pound per 100 pounds of body weight in young, growing horses; mares in late pregnancy; or those lactating. Mature pleasure horses, mares between 40-200 days pregnancy or in late lactation and some performance horses can have hay intake limited to ½ pound per 100 pounds of body weight with appropriate adjustment in grain intake.

Owners have several other practices that can allow them to stretch limited or expensive hay supplies. A few changes in feeding practices that may be helpful are the use of all-in-one feeds, hay cubes and /or alternate forage or fiber sources.

All-in-one feeds contain a forage source that results in a relatively high fiber content. If hay is included in a pelleted or meal form or an all-in-one feed, it will be processed. Chopping and/or grinding of the hay will result in short or even fine pieces. Because of this process, it is recommended to feed some longstem hay with all-in-one feeds. The amount of long-stem hay may be limited to ½ pound per 100 pounds of body weight, but always feed at least 3-4 pounds of long-stem hay in all situations.

Other sources of roughage-type feeds that can be added to grain to stretch the hay supply are beet pulp or soybean hulls. The latter two feeds are highly fermentable fiber sources and are frequently added to rations for performance horses. In these rations, beet pulp and soybean hulls provide an energy source as well as some fiber content for high-level performance horses. If hay is limited, beet pulp or soybean hulls are used primarily to add fiber to a horse’s diet. For example, the use of these two feeds with performance horses would allow hay intake to be limited. The hay saved by this feeding practice could be fed to young, growing horses or late pregnant or early lactating broodmares.

Beet pulp can replace hay pound-per-pound. Approximately ¼ to 1/3 of mature horses’ hay can be replaced by beet pulp. When 3-4 pounds of beet pulp are fed, it can be mixed with the grain. Larger amounts should be soaked and fed separately. Beet pulp produces a low-dust feed.

Since alfalfa hay is commonly fed to and liked by horses, alfalfa cubes or wafers are often used as a forage source. Alfalfa cubes become more important when hay is limited, poor-quality or more expensive than alfalfa hay. Cubes or wafers are about 1 ¼-inch square and 1-3 inches long. Pellets are normally ¼- 3/8 inch in diameter and about ½-inch long. Alfalfa cubes have similar nutrient composition to alfalfa hay. Another advantage is they are more easily stored, taking less space than hay and resulting in less wastage. Less manure is produced when horses are fed cubes. This manure reduction, which may be up to 25 percent, can be important in certain management situations such as horses kept in a suburban environment.

Alfalfa cubes can replace hay pound-per-pound. If a horse was being fed 18 pounds of long-stem hay, feed only four pounds of long-stem hay and 14 pounds of alfalfa cubes. It is important to limit the feeding of alfalfa cubes. If provided free-choice, horses will consume more alfalfa cubes than longstem hay by 17-25 percent.

When alfalfa cubes composed 60 percent of the ration for weanlings, average daily rate of gain was acceptable, exceeding moderate growth. Weanlings averaged greater than 1.5 pounds of gain, and it was concluded that the use of alfalfa cubes for weanling horses produced adequate growth response.

It has been suggested that horses will chew wood, such as fences, stall doors and partitions, when fed pelleted or cubed feeds. When horses were fed 2.5 percent of their body weight as long-stem alfalfa hay or alfalfa cubes, there was no effect of type of feed on the incidence of wood chewing. Other factors, such as weather or boredom, are more likely causes.

Feeding Management. Often, problems observed in feeding programs are not the feeds but the management or manner in which feeds are stored and fed. In other words, feeding management is the key to good nutrition after obtaining the appropriate high-quality feeds for a particular type horse.

Hay should be good to high-quality for horses. It is not recommended to feed poor or even fair-quality hay to horses.

Horses should never be fed moldy or dusty feeds. Hays are more likely than grains to be musty or moldy. Rain during hay harvesting results in moldy hay. When rain-damaged and moldy alfalfa hay was fed to weanling horses, they gained less weight and did not grow as tall as weanlings fed undamaged hay. Rain-damaged hay probably depresses nutrient digestion. Weanlings eating moldy hay also had damaged livers that did not function properly.

Dusty hays are not good for horses either, since horses are prone to respiratory problems. The two major sources of dust to stabled horses are hay and bedding, with mold spores in hay the main culprit. All hays have some mold spores. If it was baled damp, it will have more mold spores.

Wetting or soaking hay reduces a horse’s exposure to dust. Any wet or soaked hay not consumed by a horse from the last feeding should be removed before feeding the horse additional wet or soaked hay. Only wet or soak hay one feeding at a time. Soaking or wetting poor-quality hay is not recommended, as such hay has a low nutritional value and should not be fed to horses.

Slightly dusty hay can be fed to horses outside. If horses are stabled at night, feed them wet or soaked hay in the evening and feed their morning hay allowance outside in a pasture or paddock, if possible.

Large, round bales of hay are currently common. In some areas, it is not easy to get the typical square bales of hay that are normally fed to horses. Round bales of hay that are stored uncovered outside on the ground should not be fed to horses. Round bales of hay intended for horses should be stored inside a shed or under some protective cover, and off the ground either on a suitable floor, on wooden pallets or old tires,

Of major concern with round bales of hay are mold and dust. Hay stored directly on the ground can mold on the bottom. It is difficult for round bales to be completely free of mold, especially in the center.

It is difficult for most horse owners to handle and store round bales. If you have the handling equipment and storage space, it is still hard to get the amount of hay needed to feed each horse separated from a round bale. Only in this manner can the hay be inspected for mold. This process is more labor-intensive than feeding square bales of hay.

Feeding round bales of hay outside to a herd of horses results in the hay being exposed to the weather, and the area around the round bale or the round bale feeder becomes muddy.

In some management systems, feeding hay on the ground outside or on the floor of a stall is a common practice. It is not recommended to feed hay on the ground or stall floor. Even if parasite reinfestation is not a problem, hay wastage is. Yearling horses fed hay in feeders gained 18.3 percent more than those fed hay on the ground. It was estimated that the yearlings wasted about 18-20 percent of hay fed on the ground. The ground was hard and dry in this study. In the south in winter, the ground is usually wet and often muddy. It is assumed that wastage of hay fed in these conditions would be even greater than 18-20 percent.

Feeding hay on the ground is definitely not advisable when hay is limited and/or expensive. Young, growing horses will not grow as rapidly in this type feeding arrangement, so it takes more grain to obtain desirable growth, especially in young horses intended for sale or early performance. The extra grain adds to the expense of feeding hay on the ground.

Since it is difficult to make high-quality hay if it is rainy, mold inhibitors are used to preserve hay baled in these conditions. Organic acids, such as propionic and acetic acids, are normally used in this process. These two acids occur naturally in the horse’s lower digestive tract.

No mold was observed in high-moisture hay treated with these two acids. When fed to yearlings, no difference in intake of treated and non-treated hay was noted. Weight gain and feed efficiency between the two groups of yearlings were similar.

In another study, when horses could choose treated or non-treated hay, they ate about three times as much non-treated as treated hay. Horses may not readily eat treated hay; however, if only treated hay is fed, horses will usually consume it at a normal level within a few days.

Hay from last year may be available, which is helpful when hay is limited or expensive. You need to be aware that hay loses dry matter content over the winter. When purchasing hay in the growing season and storing it till winter, you need to realize that the hay will lose about 5 percent of its weight over time. Two tons (4,000 pounds) of hay purchased last summer and stored for winter feeding will actually be about 3,800 pounds. You must consider this loss when purchasing hay to insure an adequate hay supply.

Most of the loss of dry matter occurs during harvest, due to moisture reduction in the curing process. Hay stored outside will lose even more dry matter. Grass hays will lose 12 percent and legume hays will lose at least 15 and maybe as much as 30 percent.

Most of the loss in early storage is non-structural carbohydrates, which horses readily digest. The result is a higher fiber hay. Fiber content is not lost in storage. The net result is a decrease in the digestibility of the dry matter. So, there is less energy available, and more hay must be fed.

Stored hay also loses protein. In a year, protein levels would decrease 0.7 to 1.3 percent. Now, this is not a lot; however, it could be meaningful to young, growing horses, late term pregnant or lactating mares.

Carotene, the precursor of Vitamin A, decreases 50 percent after 18 weeks of storage.

You should purchase at least 5 percent more hay than needed. If feeding year-old hay, when new hay is limited or expensive, feed about 5-10 percent more.