by Cynthia McFarland

Horses are certainly adaptable. They have proved this by thriving in settings that are hardly natural for an animal that was designed to graze for the greater part of every day. When supplied with proper healthcare and nutrition, that same animal can live in cities, deserts, stalls, and dry-lot corrals with nary a blade of grass in sight.

Any equine expert will vouch for the fact that good pasture supplies both nutritional and substantial mental benefit for the horse. Yet maintaining a healthy stand of grass requires effort and expense. Extended grazing and hoof traffic take a toll on horse pastures. Lack of adequate rainfall can have serious consequences, which is why some farm owners must rely on irrigation.

"Under the severe drought-like conditions that much of the [United States] has been having, you're going to have to have some sort of supplemental water source if you're going to have reasonable pasture growth or hay production," said William A. Schurg, Ph.D.,  professor and equine specialist at the University of Arizona.

"Drought has been a challenge in several parts of the country. In areas receiving heavy rain and snowfalls, even though the moisture has helped, farmers can't get as many hay cuttings because they can't get into the fields as early.

"Additionally, the changing environmental conditions, various emergency situations—such as the fires and mudslides in California, tornadoes and hurricanes in other parts of the country—have had a huge impact on forage production nationally, along with the rising costs of fuel and water. As a result, there has been a huge increase in hay prices, and that's impacting the overall horse industry right now. I think this is and will continue to be one of our more challenging issues in the future."

Whether the land is used for grazing or hay, forage production depends completely on environmental influences. The cost of establishing and maintaining pasture must be considered when irrigation comes into play.

Three types

Three basic types of irrigation are used for horse pasture and forage production: sprinkler systems, flood irrigation, and wheel irrigation systems, which are moved by tractor or automated programming. Flood irrigation requires that the ground be completely level, which can be a substantial cost when setting up such a system. To avoid the cost of leveling pastures, horse owners with small acreage usually depend on sprinkler systems for irrigation. Wheel irrigation systems are more frequently used for forage and crop production than for pasture irrigation.

The University of Arizona's horse farm in Tucson houses approximately 50 horses at all times. Its Thoroughbred breeding program produces about a dozen foals annually, which are consigned to the Arizona Thoroughbred Breeders sale as yearlings each October. Students have the advantage of working with these horses from conception through the yearling sale on numerous related projects.

"Here in the Southwest with just 12 inches of rainfall a year, that's not sufficient for pasture, so irrigation is mandatory," Schurg said. "In Arizona, we see more flood irrigation than rotational sprinkler systems. With flood irrigation, you have to go in and laser-level the ground so you get uniform distribution of water."

At the university farm, each pasture has two or three sites where water is dispersed from large valves. When these valves are opened, water is allowed to flood freely onto the pasture until it is two to four inches deep, and then allowed to soak in. Frequency of irrigation depends on the size of the field and environmental conditions. For example, high heat or windy conditions will require more frequent irrigation.

To provide year-round grazing, the university farm overseeds its native Bermuda grass pastures with a combination of perennial and annual cool- season grasses (annual rye, wheat, oats, and barley) for grazing from October through April. From April through September, the Bermuda grass thrives in the heat, provided it is watered regularly and not overgrazed.

"Pasture management really varies, depending on the region, elevation, and rainfall," Schurg said. "Here in Tucson, alfalfa, Bermuda grass, perennial rye, and a grain seed combination seem to work reasonably well, but when you get up to higher elevations, you may need fescue or other types to grow more successfully."

Each pasture at the university farm is at most two to three acres. A great benefit has been dividing pastures into one-acre sections with electric fencing to allow for rotational grazing. This allows pastures to be used most effectively to provide a reasonable amount of forage on a daily basis.

"Rotational grazing is helpful if you have high stocking rates and low pasture availability," Schurg said. "We put seven to ten horses on a pasture for about a week, and then rotate them off to another field."

Horses are off each pasture for a minimum of 30 days to as long as 50 days. During that time, pastures are typically irrigated two to three times, dependent on any rainfall that may occur. In recent years, Tucson has had 30 to 60 days of 100-degree weather with relatively limited precipitation. Rains typically occur from mid-June to mid-September, so pastures usually will not require irrigation as frequently during that period.

Even with irrigation and overseeding of pastures, Schurg said there are three to five months of the year where supplemental hay is still required. "But we can reduce our hay feeding by having horses out on pasture, and this helps the bottom line significantly in the area of high hay costs," he said.

Golden Eagle

Golden Eagle Farm in Ramona, California, must irrigate to maintain its pastures.  The farm, which has two separate divisions totaling more than 700 acres, plants Bermuda grass for the warm months and annual rye during the winter. The in-ground sprinkler irrigation system has removable nozzles, and the entire system is out of sight when not in use. The system usually runs every day during the spring and summer, when horses are taken off the pastures for a short time.

When rain occurs, the farm can go one or two days without irrigating. Horses are given supplemental hay, primarily an orchard grass-alfalfa mix, and pastures are rotated as much as possible to maintain grass stands.

"We have two facilities, and the west division for yearlings is about 232 acres," said Janine McCullough, general manager of Golden Eagle. "It has rolling hills and doesn't seem to take as much of the dead heat or wind, and the grass grows really easily. We haven't had as tough a time on this section with irrigation. Being in Ramona, it's desert-like. We'll have snow, and then in the summer months it can get well into the 100s, which makes grass and water troublesome."

Located near San Diego, Golden Eagle went through the severe wildfires that devastated much of the area in October 2007. Remarkably, the farm was virtually untouched, while neighboring operations suffered serious damage.

"The last fire was so much worse than the fires four years ago, due to the strong winds that were switching directions," McCullough said. "The thing that probably saved us was that we have all chain-link fences. The fires burned to the fence lines and traced the whole exterior of the farm. It didn't have any fuel, and all our barns are concrete block."

Some six months after the fire, more grass than usual is growing. "I've heard that the ash from the fires is actually working as a fertilizer," said McCullough. "We noticed it a little after the fires four years ago, but more this time. This is the first time in almost five years that I've seen this much grass."

Golden Eagle relies on the expertise of equine nutritionist Stephen Duren, Ph.D., to assist in their nutritional program. Horses are weighed every 30 days to chart growth, and Duren visits the farm every three months. He looks at the growth curve that has been recorded for each horse and advises accordingly on their individual feeding program.

"After working in Kentucky for several years and then coming to California, I think pastures in our area are more for the benefit of horses being outside," said McCullough. "Horses are grazers naturally, and it's good for them mentally to be outside. We have a very good nutritional program and just use our pastures as a place for babies to play, grow, and lay down some bone, and for racehorses to rest. Every farm has to adjust to the climate conditions in their area. In Santa Ynez, grass grows very differently than here in the valley. I've seen some farms there where I'd have to change my feeding program because of the grass growth."

Practical considerations

Depending on geographical location, zoning regulations may impede your ability to irrigate. In addition, if your farm is on city water, the cost of irrigation may be prohibitive. If your farm is on well water, you have to consider water availability, well pumping capacity, and electric costs. Depending on your area, you may be able to purchase waste water at a more reasonable cost.

Irrigation of pastures is not common in the horse country of Kentucky or Florida, even though recent years of drought may have some farm owners contemplating that thought.

"It's not practical or worth the cost to put in irrigation in this area because of the normal rains that occur during the growing seasons," said Mark Shuffitt, University of Florida/Marion County extension agent in Ocala. He noted that the cost to put in a good irrigation system is difficult to justify in regions where annual rainfall usually is adequate for growing and maintaining a productive horse pasture.

That does not mean farm owners do not come up with ways of battling dry weather.

"Last year we saw people using sprinklers and hoses," Shuffitt said. "You can help a small piece of land to survive by making provision for temporary irrigation with hoses and tall sprinklers that can be moved around just to help grass survive in times of severe drought."

Shuffitt stressed that, even in dry periods, you can help pastures come through if you pay close attention to stocking rates and incorporate a rotational grazing program.

"You have to pay attention to the basics," he said. "Stocking rates and management are so important. People often want to stock heavily, but not do the management practices to keep the grass there. If you want to save your pastures, use rotational grazing and give the pastures enough time to recover."

A good rule of thumb is to remove horses from pasture when they have grazed the grass down to an average of three to four inches in height. If you allow grass to be grazed very short, it is much more difficult for the plants to rebound. In addition, the shorter the grass, the more moisture evaporates from the soil, which only compounds the challenge of maintaining a good stand of grass.

Rotate horses off pasture until grass grows back to a height of six to eight inches. This will usually take a minimum of 21 to 30 days, and longer if you do not irrigate or have not had sufficient rainfall.

Walk pastures regularly to get a close look at how grass is—or is not—growing. You are sure to notice more than you would driving the pasture in a vehicle. Experts say this is one of the best ways to observe pasture condition and stay on top of potential problems, such as weed outbreaks, before they get out of hand. 

Cynthia McFarland is a Florida-based Thoroughbred Times correspondent