One of the by-products of horse ownership is dealing with equine by-products, less delicately known as horse manure. The average horse produces about 50 pounds of fecal waste a day. Mix in soiled, wet bedding from the stall, and you’ve got 95-100 pounds of smelly waste that has to be removed and disposed of properly.

It’s not a problem that resolves itself, except possibly on large pastures with low stocking density. Raw manure, if left to accumulate, serves as a breeding ground for parasites and attracts biting flies. If raw waste accumulates in the stall or other confined spaces where the horse spends its time, the horse risks developing thrush and other hoof problems. In a dried state, vast amounts of manure can lead to a dusty, spore-laden environment where both human and animal can suffer respiratory distress, lung problems, allergic reactions, and eye irritation.

Proper waste disposal is not a matter of aesthetics; it’s an integral element of horse health and management. It’s also an environmental responsibility. The EPA currently is developing regulations that govern waste disposal at animal feeding operations, possibly including large horse farms, show areas, racetracks, etc.–basically anywhere large numbers of animals are confined, fed, and produce fecal waste.

Several options exist for dealing with equine waste, including composting, spreading, burning, and hauling. The option that works best depends on size of the farm, stocking density, available equipment and/or labor, and budget.

Spreading

Attorney Anita V. MacLean, PhD (Land Use Management), owner of a 400-acre Morgan horse farm named ValMac, in Sayre, Penn., says that many large farm operations prefer to spread fresh or composted manure on croplands or unused pasture. The advantage of this method is the enrichment of soil via the humus and rich nutrients contained within the manure, especially if manure is tilled into the ground rather than just spread on the surface.

The disadvantages are the cost of a tractor and harrow, the possibility of introducing pasture grass or weed seeds onto croplands, the labor of transporting manure to croplands, and, when using a manure mix that contains sawdust or wood chips, the risk of nitrogen depletion and stunted crop growth. “The nitrogen that would normally go to the crop goes to the wood chips first,” MacLean says. Additionally, if fresh manure is spread onto the horse pasture, the horses must be kept off that pasture during the period it takes for fecal matter to break down and parasite eggs to die.

Manure should be spread uniformly to ensure the piles break down evenly. Otherwise, ammonia and salts from the manure could become too concentrated and kill vegetation.

On croplands, manure is spread before or after the growing season.

“In the northeast, many farmers wait until winter to spread, utilizing the theory that the nutrients from raw manure will seep into the ground after the thaw,” says MacLean. “On our farm, we spray fertilizer on the land, then till in the manure in early spring. This prepares the ground for planting.”

MacLean advises that farmers concerned about crops being stunted due to manure mixed with sawdust or wood shavings should add nitrogen fertilizer to the mix or to the soil.

“The fertilizer can be added to the manure prior to spreading it on the soil,” she says, “or the fertilizer can be mixed into the soil after the manure has been applied.”

Spreading and harrowing manure on horse pastures should be done only in the coldest or hottest, driest weather to ensure larval kill, and should not be done during the season of parasite activity, says Douglas E. Hutchens, DVM, clinical assistant professor, University of Illinois.

“When there is adequate rainfall and the weather is good, you will spread more larvae across your pasture,” he warned.

Experts differ on how quickly horses can be returned to pasture after raw manure has been spread. Michael A. Schmitt, PhD (agronomy), associate professor/extension soil scientist, Department of Soil, Water, and Climate, University of Minnesota, says that generally six months is long enough for sunlight, temperature, and surface microbial activity to de-activate most of the pathogens harmful to horses. However, this might vary depending on the type of parasite load the horses carry. (The eggs of ascarids can live in the soil for up to nine years.) Consult with your veterinarian and cooperative extension service for recommendations pertinent for your situation.

One other type of spreading is the equine do-it-themselves variety. On large pastures, horses tend to graze in one part and defecate in another, so the elements of nature might take care of the manure problem as long as the horses are on a good deworming program and parasite load is at a minimum. Such is the case with the herd at Kansas State University, where stocking density is five or six horses per acre during the grazing season. But, MacLean cautions, “If you have a high turn-around of horses or if you have had worm problems during the year, horses allowed to graze near their own manure are quickly re-infested.”

Composting

This is the process where manure and soiled bedding are heaped into a pile to decompose. During the process, the mass heats up, killing off many parasite eggs and weed seeds. When fully composted, the pile is reduced in size and mass and will turn into a dark, loam-like fertilizer that can be spread on gardens, fields, and pastures. Be sure that compost to be spread on pastures truly has matured enough to kill parasite eggs, and that ascarids (which can survive a long time) were not part of the parasite load. Otherwise, you can spread parasites around the pasture. Horses can be returned to pasture in which properly composted materials have been spread in about two weeks, MacLean says.

Composting is an inexpensive and beneficial way to utilize manure, although it takes time, requires some attention to maintain a compost heap properly, necessitates a composting site, might require a tractor or front end loader, and, if not properly constructed, it can create an offensive odor.

Compost piles can be built in vertical stacks, horizontal windrows, or amassed in bins. Bin and vertical stack composting work well for one- or two-horse operations; windrow composting is better for operations with large herds and sufficient space.

Depending on the amount of materials and how diligent the horse owner is in turning the compost pile, composting can take one month to several months.

“The pile should be turned regularly. The more you turn it, the faster your compost will be ready,” explains MacLean. “This oxygenates/aerates the pile, allowing oxygen to get to the bacteria and organisms so they can break down the manure. Air naturally permeates the compost pile to a depth of about two feet; however, with the average horse producing more than 50 pounds of manure a day, piles quickly exceed two feet in height. While a small tractor can aid in turning the pile, an easier way to get air deeper and avoid turning the pile as frequently is to insert a couple of PVC pipes into the center of the pile.”

The compost should be kept damp; in the summer it might need to be watered. Compost is ready when the material looks evenly textured and crumbly (like dirt).

Correct siting of the compost pile is important.

“Avoid placing the pile in a low-lying area as it will turn into a stinky, liquid mess due to fluid accumulation,” says MacLean. “Instead, put the pile on an elevated area and, if possible, 100 feet from wells, streams, barns, or horses to avoid leaching during heavy rains. Divert runoff away from stockpile and grazing areas to prevent re-infestation of parasites.”

If your facility is smaller and you plan to utilize the bin system, select a site large enough to fit the number of bins needed.

“You’ll need at least two bins,” MacLean states. “Two bins or more result in faster and more efficient composting. Completely fill one bin first with manure and stall wastes, then start filling subsequent bins, one bin at a time. If you fill your bins one at a time, materials in previous bins will compost, resulting in a quicker product.”

Bins are easy to build. Ideally, build the size or number of bins to accommodate all the waste materials accumulated for several months of composting. A concrete floor and strong walls are handy for larger bins, and a gravel access is convenient for loading or using a wheel barrel to bring the manure to the heap.

“To prevent the piles from becoming soggy in the winter and too dry in the summer, cover them with large tarps,” MacLean advises.

For the vertical compost pile, material is added to the top or sides of the mass. While frequent turning or inserting pipes will hasten decomposition, some horse owners build a new pile once or twice a year and only turn the piles a couple of times within a year, letting the pile slowly decompose over a year or so.

The windrow pile typically is about five to six feet tall and six to eight feet wide. Materials are added at the end of the pile, hence the pile can grow to any length. Generally, these piles are turned with front-end loaders or specially equipped tractors.

Hauling

In situations where there is limited time or space, horse owners might transport the manure off the premises. Arrangements might be made with local nurserymen, gardeners, or farmers who want to retrieve composted manure themselves (fresh manure will burn vegetation).

An alternative method of hauling–although more expensive but less labor-intensive–is the owner taking composted or fresh manure to the landfill (a dumping fee usually is charged) or paying a hauler to take the manure away.

Burning

Where zoning regulations permit, burning manure can be a fast and efficient method. Allow the manure to dry by spreading it out. When dried, gather the pile in an open, bare area away from pasture, dry grass, and buildings, and where the smoke and smell won’t offend neighbors. Set the pile on fire; it will smolder and burn slowly like charcoal.

Additional Resources

To learn more about composting and waste disposal methods, consult with the agriculture department at your local or state college or university, your local cooperative extension agent, or documents posted on university web sites