Pasture Perfect

Lead your horse out to his turn-out paddock and let him loose on that lush spring turf. Chances are, he'll let you know how much he enjoys his liberty by tearing across the field, his tail flipped up over his back; he might even throw in a couple of exuberant bucks just to emphasize the point.


Red clover, a common legume for horses.

Maintaining horses on pasture rather than in stalls has several advantages. Not only does it cut down on barn chores and the amount of bedding your operation will go through, but it provides horses with the chance to exercise themselves at will, naturally building strong bones and muscles, and relieving stress through running and playing. Allowing horses to graze also cuts down on feed costs, and might reduce the risk of digestive upset by more closely matching their natural feeding patterns. Horses which are allowed to graze and socialize generally are happier and more pleasant to deal with. All in all, it's a win/win situation.

Grazing Behavior

The ideal pasture has good grazing--enough to keep each of its inhabitants busy throughout the spring, summer, and autumn months--with no harmful or poisonous plants in reach. In an area with rich soil and a welcoming climate, one acre per horse is usually enough land to provide good, steady grazing throughout the year, but in places with poor soil conditions, such as in the Rockies, a great deal more land (perhaps up to 30 acres per horse) might be needed to supply an adequate amount of forage. But even a small pasture is better than none, and small pastures can be managed in order to provide some green forage, if they are not neglected or overgrazed.

If living outside on 24-hour turn-out, adult horses spend 60-80% of their daylight hours grazing, with the preferred hours being early morning, late afternoon, evening, and in the cooler hours in the middle of the night. (They also spend 5-10% of their time lying down, especially in the three to four hours before dawn.) During their grazing time, they will consume about a tenth of a pound of forage per 100 pounds of their body weight--every hour. So, for example, an average 1,000 pound horse will eat about a pound of forage per hour. Horses which have more limited turn-out time seem to know it; they can consume up to three times as much plant material per hour. (And while horses would prefer to spend 12 hours a day or more grazing, it's by no means necessary--they can take in enough forage to meet their daily dietary energy needs in four to five hours on good pasture.) The amount of time spent grazing can be adversely affected by factors like severe weather (either hot or cold) or an abundance of annoying flies, and horses on their own tend to eat less than those with equine companionship. Young horses also seem to spend less time grazing than their more mature counterparts, perhaps because they're more easily distracted and willing to play.

Horses are selective grazers, unlike most other livestock. Left to their own devices, they wander, choosing the choicest morsels and rejecting other plants. Where they deem the grazing to be unsuitable, they make manure piles--and the fertilizing effect this has means the unwanted plants grow and go to seed that much faster, while the preferred grazing gets cropped closer to the ground. (Horses have an aversion to grazing near their manure, so the borders around these "rest stations" can become quite large.) Where overgrazing has occurred, weeds quickly take hold, replacing the more nutritious grasses. The result is a very patchy pasture, and depending on the plants growing there, it can compromise the overall quality of the forage. Legumes and grasses like alfalfa, clover, brome, and bluestem struggle to regenerate if they are grazed to more than 50-60% of their original height; but others, such as bahia grass, orchard grass, Kentucky bluegrass, and Coastal Bermuda grass, which are commonly grown in the southern United States, actually thrive when grazed thoroughly and cropped close to the ground.

Choosing the right plants for your pasture is half the battle in grazing maintenance; correcting that patchy grazing pattern also is key. Most agricultural experts recommend a two-pronged approach; first, mow your pasture periodically with a bush-hog to take down the tall weed growth, and second, scatter the manure piles with a chain harrow to prevent concentrated patches growing up and more evenly fertilize the rest of the pasture. If the weeds threaten to take over, you might have to consider using a herbicide such as 2,4-D or RoundUp, but if you do so, keep in mind that a broad-leaf herbicidal product also will kill legumes like clover and alfalfa (although not most grasses). Naturally, when using herbicides, it's essential to follow package directions to the letter. Spraying a pasture with a herbicide generally will mean you have to keep horses off the field for at least a week or two (depending on the chemical you use). If the safety instructions are not clear on this point, make sure you consult with your agricultural extension expert as to the exact parameters for horses before you go ahead.

A more natural approach is to share your grazing with another species. Both sheep and cattle are more systematic grazers than horses are, and they are far less particular about grazing near the manure piles, so they can help keep a pasture evenly cropped. (They also are better equipped to process poorer-quality forages than horses are, so they can make good use of the plants horses reject.) Even domestic deer can be an appropriate choice for a shared pasture (providing your fencing is up to enclosing them), since they and horses tend to select different plants.

Pasture Value

The nutrient content of a pasture is highest during spring and fall growth. Generally speaking, the more immature a plant is, the more nutritious and palatable it is; but an immature plant also is smaller than a full-grown one, and thus provides less food overall. A good Kentucky bluegrass pasture in full spring growth can provide almost as much digestible energy, and more protein, than a comparable quantity of oats (which explains why young horses tend to grow rapidly on lush pasture, and mature horses tend to become overweight). But pasture grasses decrease in nutritive content as they mature. From the mid-vegetative stage (about two to four weeks of growth, or about two-thirds of the grass' mature height) to seed-forming maturity (about 12 weeks of growth), pasture plants can lose from one-third to one-half of their digestible energy and protein. The concentration of some minerals decreases as well. There is little change in calcium, zinc, or sodium levels, but potassium, phosphorus, magnesium, manganese, and iron levels all decrease by as much as half as grasses mature. (Phosphorus and copper can decrease from spring to summer, then increase again with a pasture's regrowth in the fall.)

Optimum nutrition is gleaned from grazing when the pasture is at the just-before-flowering stage, when the bright emerald green color of immature plants is gradually turning to the richer, darker green of mature growth. If the pasture is beginning to take on a yellow or brown appearance, it is overmature; once the plants have seeded, both their nutritive value and their palatability plummet. The best solution for an overmature pasture is to mow these plants down to scatter the seeds and encourage new growth.

If you don't have the luxury of limitless pasture, it's worth taking some care with regard to pasture management to prevent overgrazing. One simple step is to avoid turning horses out on very wet fields in early spring; the damage they do to the turf might make it difficult for the plants to recover. Once the pasture is dry and horses are grazing, monitor the forage growth, and try not to let your horses mow the grasses down to less than two inches in height. In late autumn, aim to leave your pastures with four to six inches of healthy growth before the killing frost; this will ensure its quick recovery in the spring.

If your pasture is in danger of being overgrazed, the best approach is to remove the horses from that field, returning them only when the plants are close to seeding again (a process that might take a month or more). Simply tossing some additional hay into the paddock won't do the job, unfortunately, as horses show a marked preference for green growth over dried hay. Try to prevent overgrazing if you can; if your paddock becomes grazed to the ground, the cost to renew the pasture can be considerable.

You also might wish to consider rotational grazing as a solution to patchy pastures and overgrazing. Studies on groups of eight yearlings on a 5.2-acre alfalfa pasture have indicated that continuous grazing on a single pasture tended to yield about 25 days of grazing before overgrazing became apparent; but when that pasture was divided into six equal sections and the eight yearlings were rotated from section to section, it was 37 days before any overgrazing was noticed. Yearlings on the rotated pasture also took in considerably more forage per day, and gained more weight (1.3 lbs. per day, on average, vs. 0.5 lbs. for the yearlings on the single pasture). Rotational grazing can allow you to achieve the maximum forage yield from a limited piece of land.

Dividing up your pasture into sections can be done simply by using portable electric fence (choose a highly visible tape rather than a single strand of wire); each section should be large enough that it takes 10 to 14 days (in the growing season) to be grazed down by the horses. After two weeks' worth of grazing, give that section of pasture a month's rest, after which it should be ready to be used again.

Improving Your Field Yield

Horses do some of their own field fertilizing, but it's not even or efficient. In order to encourage good pasture growth throughout your field, you should consider applying fertilizer periodically. The type you choose will depend on the results of a soil analysis, which you should test every couple of years. (Twenty or more one- to two-inch core samples of the top four inches of your topsoil, excluding plant material and surface litter, collected with plastic or stainless steel tools without rust, are mixed together for a standard soil sample.) Your local agricultural extension agent or farm store should be able to advise you on the best fertilizer to use, and the best time to apply it, based on the results of the soil analysis.

For many pastures, an application of nitrogen fertilizer might be all that's needed, according to Kevin Rogers, a soil and pasture specialist at the Durham Farmer's Co-op in Grafton, Ontario. An application of this type of fertilizer on the surface of the pasture in early spring can encourage lush growth and often will make your pasture last longer. Rogers advises a second application approximately eight weeks after the first (for instance, in April and again in June) to encourage better growth in warmer weather. Proper nitrogen fertilization of a grass pasture not only increases the amount of forage produced, but also its protein content. A Bermuda grass pasture that receives nitrogen, for example, can produce up to eight times as much forage with 2.4 times as much protein-a substantial economic benefit.

Pastures that contains more than 40% legumes (such as alfalfa or clover) likely will not need nitrogen fertilization, as these plants manufacture soil nitrogen in their root nodules, not only fertilizing themselves, but benefiting the rest of the field as well. Many pastures don't have this concentration of legumes, says Rogers, because they don't make particularly hardy pasture plants. If you do have a legume-rich pasture, it might require minerals such as phosphorus, potash (potassium carbonate), and lime (calcium oxide); otherwise, the legumes can die out before the grass portion of the pasture. Other minerals that pasture might require include magnesium, sulfur, and trace elements like copper, manganese, zinc, and boron (which can be beneficial if you plan to graze broodmares or young horses on the field).

If you have an existing pasture that you'd like to upgrade without plowing it under and starting from scratch, consider "overseeding" (also called topseeding). An application of a "pasture mix" of seeds in early spring, at about half the density you would use if planting a new field, can help increase the density of nutritious forage without breaking up the ground. Rogers notes that "frost seeding" is one particularly effective approach: the seed is applied to the pasture at a time when the ground is still frozen, but has no snow cover. When the soil warms in the spring, it "heaves" as the frost leaves it, drawing the pasture seeds into the earth and giving them a better chance of germination. You also might choose to go over your topseeded pasture with a roller or chain harrow to help plant the surface-scattered seeds. After topseeding, allow at least a week for the seeds to "take" before returning horses to the pasture.

Which Plants To Plant?

A good pasture includes a mix of forage plants, each with its own growing pattern and benefits. Which ones you choose will vary a great deal depending on your local climate, soil type and condition, drainage, local incidence of plant diseases and pests, and how hard you intend to use the pasture. Generally, though, you can include five different types of plants: warm- or cool-season perennial or annual grasses, and legumes. Annuals, such as winter wheat (a cereal grain sometimes planted for grazing purposes), must be planted yearly, but perennials and legumes, if not overgrazed, will continue to come back year after year. The advantage of annuals is that their nutritive value is generally higher than that of perennials, with cool-season annuals being the highest.

Bermuda grass, bahia grass, and digitgrasses like pangola are examples of warm-season perennials. They produce their major growth during the summer, and don't grow well in areas which have cold winters. Cool-season perennials such as reed canary grass, fescue, brome, and orchard grass, on the other hand, grow most rapidly in the spring and fall seasons and endure cold winters well. They tend to produce little to no new growth during the hot summer months, however.

Warm-season annuals include sorghum, Sudan grass, and Johnson grasses. They are of limited value in horse pastures as a rule. But cool-season annuals such as the cereal grains can provide a concentrated amount of very nutritious grazing for a short spring season without decreasing their yield when harvested for grain and straw later in the summer. In areas where winter wheat is grown, livestock commonly are grazed on the young plants during early spring (February and March in the central United States), and if the wheat is not to be harvested, it can be grazed for an additional two months or so, providing higher protein and digestible energy than alfalfa. This makes it particularly appropriate for young horses, although calcium levels might have to be supplemented since they are quite low (as is true for all cereal grains).

Legumes (such as clovers, alfalfa, vetch, and birdsfoot trefoil) are higher in protein, calcium, dietary energy, and most vitamins than virtually any type of grass forage. And because they produce their own nitrogen, they are in a sense "self-fertilizing," improving the nutritive content of an entire pasture and even improving the physical condition of shallow clay soils. But they are less tolerant of extremes in weather and poor soil conditions than grasses, and because they don't form dense root "mats" the way some grasses do, they're less hardy in a situation where they are regularly trampled. (Rogers notes, however, that birdsfoot trefoil can be very useful in pastures with low, wet areas, where it roots and grows better than most other plants.) Legumes are of most benefit when they are included as part of a pasture mix; they will grow during periods when warm-weather perennials shut down, prolonging seasonal forage production for the pasture, and most horses also consider them more palatable than grasses. Many agricultural experts consider a mix of 60% grasses and 40% legumes to be ideal for horse pastures.

Here's a brief run-down of the more common pasture forages available in North America:

  • Alfalfa (Medicago sativa) is a deep-rooted legume that is highly palatable and does best on slightly acidic soils. It tends not to grow well in the southern United States because of a high susceptibility to hot, humid conditions, insects, and diseases, but is a pasture (and hay) staple in the northern United States and much of Canada.
  • Clovers also are common legume forages for horses. There are a number of varieties, including Alsike clover (Trifolium hybridum), which grows best in cool, moist climates and on heavy clay soils, but is poorly palatable to horses; crimson clover (Trifolium incarnatum), a cool-season annual legume that grows well in a wide variety of soil conditions and is widely used for winter grazing in the southern United States; and red clover (Trifolium pratense), which is thick-stemmed and highly productive, but not terribly resistant to diseases and pests and thus only lives a few years as a rule. (A mold called black patch also can grow on red clover; it is not very toxic, but can cause livestock who consume it to salivate excessively.) There also are the white- and yellow-flowered sweet clovers (Melilotus alba and Melilotus officinalis), which are drought- and cold-resistant, fast-growing, and particularly popular in areas with short growing seasons, such as southern Canada. Select a low-coumarin variety if possible; coumarin, a compound contained in some sweet clovers, can be converted by molds to dicoumarol, a substance that can inhibit vitamin K in the horse's system, thus limiting the ability of his blood to clot. Finally, there is Ladino clover (Trifolium repens), a white clover that grows best on well-drained soils and in cool, moist climates. It is highly nutritious, but has a shallow root system and therefore does not tolerate drought. It is also one of the most likely forages to cause "bloat" in cattle, but thankfully it does not have this effect on horses.
  • Birdsfoot trefoil (Lotus corniculatus) is another warm-season perennial legume often found in pasture mixes; it has yellow flowers and can tolerate fairly acidic soils and poorer drainage than alfalfa, but is not a prolific producer.
  • Orchard grass (Dactylis glomerata) is a palatable, early-maturing grass that can produce excellent-quality forage, but is not as tolerant of drought, wet, or alkali soils as most other grasses. It does, however, tolerate shade well.
  • Smooth brome grass (Bromus inermis) is an excellent choice for areas with high rainfall. It is also winter-hardy and more productive than many other grasses, and does especially well when seeded with alfalfa.
  • Bahia grasses (Paspalpum notatum) are frost-sensitive and thus only suited for the southern States, where their drought resistance is a plus. They also withstand overgrazing well, but their nutritive value plummets following maturity; the plants often become so tough and fibrous that horses will not eat them.
  • Kentucky bluegrass (Poa pratensis) is likely the most palatable of all the pasture grasses for horses. Although it is winter-hardy and thrives on close grazing and mowing, forming a dense root mat, its yield is not as high as that of some other forage plants. It is also not drought-tolerant and has low mid-summer growth, but it is long-lived and low-maintenance, which makes it justifiably popular.
  • Tall fescue (Festuca arundinacea) is a grass with good tolerance for hot weather and drought, as well as wet, saline, and alkali (but not sandy) soils. It can withstand a good deal of close grazing and heavy traffic, but although it is quite nutritious, its palatability is fairly low. Because of this, its presence in a pasture mix often results in patchy grazing. Horses will greatly overgraze other plants before they will touch fescue. In addition, fescue can become infected by an endophyte called Acremonium coenphialum, which causes fescue toxicosis in pregnant and lactating mares. Broodmares nursing foals or in late pregnancy, and horses less than a year old, should never be grazed on fescue pasture unless it is known to be endophyte-free. (Endophyte-free fescue seed is now available for horse pastures, and is much the best choice.)
  • Bermuda grasses, in contrast to fescue, are well-adapted to sandy soils, but not to wet ones. Coastal Bermuda grass (Cynodon dactylon) tolerates trampling and overgrazing better than most grasses and is higher-yielding than bluegrass or timothy, although it loses much of its nutritive value when it is overmature. As a result, it's best suited as a hay crop or for rotational grazing.
  • Timothy (Phleum pratense) is a grass that thrives in northerly climates, being winter-hardy, but not particularly drought-resistant. Its palatability is probably second only to bluegrass. In the Midwest and Canada, it's often mixed with alfalfa for pasture and hay.

The combinations of these and other forage plants are practically limitless, and will vary according to local climate and soil conditions. If you are unsure as to which legumes or grasses you'd like to plant, consult with your agriculture extension agent or feed-and-seed store, who can likely recommend a pasture mix specifically formulated for your area. Once you've established your improved pasture, continue to manage it judiciously, and it will reward you a thousandfold, with nutritious, low-cost forage--not to mention a valuable place for your horses to play.

About the Author

Marcia King

Marcia King is an award-winning freelance writer based in Ohio who specializes in equine, canine, and feline veterinary topics. She's schooled in hunt seat, dressage, and Western pleasure.

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