Pasture & Range: March 2003

Although most of the forage information in Ag News and Views is produced with cattle in mind, much of it is applicable to horses also. As a forage specialist, I am occasionally asked about forages for horses, either for pasture or for hay. In this writing, I will address forages for horses only — topics to be covered include general horse/forage information, pastures and pasture management and hay.

General horse/forage information
Forages are an essential component of a horse’s diet, because they need it to help prevent digestion problems. Additionally, an adequate quantity of good-quality forage can minimize feed expenses, which is usually the single highest cost of owning a horse. Good forage management can also minimize the potential pasture problems, such as spot grazing and over grazing, often associated with grazing horses.

Unlike cattle and sheep, horses are not ruminants. Horses have a single stomach and a functional caecum, which means their digestive system is less efficient. Therefore, horses have a greater requirement for higher-quality protein than cattle, with growing and lactating horses having higher nutrient requirements than mature non-lactating animals. For optimum results, horses need to be fed often and consistently with a forage that can be easily and rapidly digested. Sudden changes or large swings in diet quality or type can cause severe and potentially deadly digestive system disorders.

Horses are spot grazers, grazing more selectively than cattle, and they tend to prefer grasses to most forbs and legumes. Rotationally grazing horses through a few paddocks works well to minimize the effects of spot grazing by allowing heavily-grazed areas time to recover. In a continuous-grazed situation, mowing or clipping the pastures two or three times a year will enhance the palatability of under-utilized areas by removing excessively mature residues.

In most instances, rotational grazing is the preferred grazing method for horses when applicable. The hooves of horses are very damaging to pastures, relative to the cloven hooves of cattle, especially when grazing newly-established pastures or pastures with excessively wet soils. Also, rotational grazing can reduce the potential for parasite infestations, especially on heavily over-grazed pastures.

Pastures
Horses prefer grasses but will consume some legumes, so horse pastures should consist of predominantly grasses but a legume presence is acceptable. Bermudagrass is the preferred pasture for horses in the Foundation’s service area because it can be easily managed for quality and quantity, and is more forgiving of intense grazing than other forages. It can also be overseeded to cool-season grasses such as rye and ryegrass for grazing during the winter. It is most preferred if managed to maintain an average sward height between 4 and 10 inches. Mowing or baling pastures may be necessary to maintain a desirable sward height and acceptable forage quality throughout the growing season, and to minimize the long-term effects of spot grazing.

Most other forages suitable for cattle are also suitable for horses but may require more management. Since horses are more selective grazers, monocultures are actually easier to manage than a diversity of forages. Fescue is almost as tolerant of grazing horses as bermudagrass. However, fescues infected with a toxic endophyte can cause severe problems for pregnant brood mares, as well as reducing weight gain on yearling horses. Endophyte-free and non-toxic endophyte infected fescues are preferred for horses. Old world bluestems are less tolerant of intense grazing, and are more tolerant of horses if grazed in a rotation. Bromegrasses, orchardgrass and wheatgrasses also make quality pasture where available, but again are not tolerant of intense grazing over a period of time. Winter annual grasses such as ryegrass and small grains make good winter pasture for horses as does crabgrass as a summer annual. Other summer annuals such as sorghums, sudangrasses, johnsongrass and their hybrids are not generally recommended as horse forages. The noted precaution is when consumed in large amounts, sorghum-type grasses can potentially cause cystitis in horses, resulting in urinary tract disorders and paralysis.

Good native grass pastures also make excellent forage for horses. However, native range is a diversity of grasses which requires additional management. Spot-grazing tendencies and hoof action of horses can rapidly degrade the native range, especially when horses are confined to small areas or to the same pasture indefinitely. Free-range grazing over large areas or in conjunction with cattle, assuming proper stocking, will minimize range degradation.

Hay
Horse hay can be produced from any pasture forage. Since horses are very selective and are very sensitive to changes in their diet, the primary requirements for good horse hay are that it be clean and leafy, free of weeds and old forage residues, free of dust and molds, and be of consistent quality throughout the supply. In the Foundation’s service area, bermudagrass is the most readily available hay that can be produced or purchased meeting the specifications just mentioned. Other pasture forages can be harvested for horses, such as prairie hay or native grass hay and old world bluestem hay. Usually, such hays tend to be of lower quality relative to good bermudagrass hay.

Alfalfa, oats and crabgrass are other forages cropped for hay. These hays are usually of high quality if properly harvested, but thorough drying may be difficult to attain during May and early June. Blister beetles, which are deadly to horses when ingested, can also be present in alfalfa hay produced in the Foundation service area.

To produce a clean, high quality horse hay, forages should be fertilized (if introduced pastures), clipped when about 12 to 15 inches in height while still immature and before excessive production prevents thorough and uniform drying, allowed to dry completely, baled without being rained on and with minimal moisture, and stored in a barn or under a cover on a well-drained site to prevent spoilage. Therefore, most horse hays in our area are produced during the middle of the summer as second and third cuttings.

By the way, hay color is not a good indicator of quality. Forage testing is the only reliable means of determining quality. Besides, horses are colorblind and are therefore indifferent about color of the hay.

For additional information about forages for horses, the Ag Division has a publication titled “Horse Forage and Forage Management” by R.L. Dalrymple and C.A. Griffith, publication number NF-FO-00-14. Another good reference is Southern Forages by Ball, Hoveland, and Lacefield, specifically Chapter 29 “Forages for Horses.”