April 24, 2018
Best Management Practices for Horse Farms
Pasture management is an important part of keeping horses and the environment healthy. Pastures provide an excellent source of nutrition for horses, and a good stand of forage helps reduce nonpoint source (NPS) pollution from surface water runoff. Many horse farms are faced with the challenge of limited acreage and high stocking rates which can lead to unthrifty and weedy pastures from overgrazing and unmanageable manure piles. Poorly managed, degraded pastures and manure contribute significantly to surface water pollution loads of sediment, nutrients and pathogens. Best management practices (BMPs) including rotational grazing, installation of heavy use areas, and manure storage and composting should be adopted to improve the overall welfare of horses and protect the environment.
Why is Pasture Important for Horses?
Horses need 1% to 3% of their body weight in forage each day, which is equivalent to 10 to 30 lb per day for the average horse. Properly managed pastures meet the forage and most other requirements for horses during the growing season. If forage requirements are not met, horses are at a higher risk for colic and gastric ulcers. Horses spend 14 to18 hours per day grazing, and travel about 10 miles per day when turned out on pasture full time. From a behavioral perspective, pastures allow horses to maintain their natural grazing behavior and exercise freely, reducing the potential for vices to develop.
Why is Pasture Important for the Environment?
Poorly managed horse pastures are a major cause of NPS pollution, which is the leading cause of water quality issues for rivers, wetlands, coastal waters and ground waters. Sediment from erosion, as well as bacteria and nutrients from manure are sources of NPS pollution that have harmful effects on drinking water supplies, fisheries and wildlife. Excess fertilizer, herbicides and insecticides applied to pastures can also contribute to NPS pollution. Properly managed pastures with dense stands of forage reduce NPS pollution by reducing erosion and surface water runoff.
Three simple, yet effective BMPs can be implemented on horse farms to reduce NPS pollution and increase the amount of forage available for grazing.
1. Rotational Grazing
Rotational grazing allows pasture plants to rest and regrow so that they do not become overgrazed. Overgrazing reduces the plant’s carbohydrate reserves and prevents regrowth. In rotational grazing, multiple paddocks are set up to allow horses to graze when the forage is at least 6 inches tall and horses are moved to the next paddock when the plants are grazed down to 3 inches tall. Pastures should never be grazed to a height less than 3 inches. Ideally, farms should plan for a minimum of two acres per horse, but with rotational grazing and intense management, higher stocking rates are possible on small acreage farms.
At the University of Tennessee’s Equine Extension and Research Center in Spring Hill, TN, a small acreage demonstration farm houses three horses on five acres with four 1-acre grazing lanes and two small heavy use grazing paddocks. During the growing season, grazing intervals last 10 to 14 days on the 1-acre grazing lanes and hay is provided in a covered round bale feeder (HayHut, Inc.) in the winter months. Allowing pasture plants to rest and regrow through rotational grazing increases the amount of forage while decreasing weeds and bare ground, ultimately preventing NPS pollution by reducing erosion and runoff. A mix of warm and cool season forage paddocks is helpful to extend the grazing season. In establishing new pastures, horses should be kept off the newly planted stands as long as possible, or until the forage reaches 6 inches in height (one to three months minimum, depending on growing conditions).
2. Heavy Use Areas
Heavy use areas are small fenced off areas that allow horses to exercise freely while keeping the animals off pastures to prevent overgrazing. They are often referred to as “sacrifice” areas because a small portion of land is given up to benefit the rest of the pasture. Heavy use areas are also used during drought or extremely wet conditions to prevent mud and damage to pastures. Some horses will get too fat with unlimited grazing, so heavy use areas can also be used to restrict access to pasture to prevent obesity or other nutritional related diseases, such as laminitis. The size of the area can vary, but generally a minimum of 150 to 200 square feet per horse is recommended with access to hay, water, white salt, and shelter within the fenced off area. The footing should consist of layer of heavy duty geotextile directly on top of the graded soil, followed by a 6 inch layer of coarse ¾ to 3” rock, followed with another layer of geotextile, topped with 4 inches of ground limestone (also called crusher run). To allow proper drainage and prevent erosion, heavy use areas should be located at the highest location in the pasture with the surface slope of 3%. If a barn or shed is located in the heavy use area, gutters should be used and water should be collected or diverted so that it filters properly.
3. Manure Storage and Composting
Manure is a major source of nutrients, pathogens and sediment that contribute to NPS pollution if not managed properly. Manure, particularly on overgrazed horse pastures, is also the culprit for the transfer of internal parasites, such as small strongyles (the most problematic parasite in adult horses today). Horses produce around 50 lb. of manure per day and 1 cubic yard of manure per month, plus an additional cubic yard of bedding if the animal is stalled part time.Best management practices for manure include proper storage and composting to minimize adverse environmental impact and health implications for horses. It is best to store manure in three- sided bins in a dry location. Ideally, bins should be covered with either a roof or tarp to decrease leaching. The storage area should be bermed and/or sloped to prevent rainfall runoff from mixing with the stored waste. If uncovered and freestanding storage piles are used, they should be constructed to shed rainfall (pyramid shaped) and located away from low lying areas were water accumulates after a rain.
Both stall waste and manure collected from pastures can be composted. Stall waste has a relatively high carbon to nitrogen ratio and can be readily composted without amendments. Manure collected from pastures needs amendments (wood chips or shavings) added to increase carbon. The compost pile should be turned (usually with a front end loader) every two to three weeks to assure that oxygen is provided to fuel the decomposition process. Water is vital and should be added during mixing to ensure the moisture content remains at approximately 50%. Proper composting can be confirmed when temperatures reach 130 to 160 °F using a long stem thermometer after several days of turning. The composting process is complete when the maximum temperature after turning is less than 20 °F above outside temperature (usually after one to four months). Once the heating stage is complete, a finishing stage occurs during which the compost matures and turns dark brown with an earthy odor (lasting two to four months). The composting process greatly reduces pathogens and increases its value as fertilizer. Composted manure should be analyzed for nutrient content and land applied as a fertilizer according to soil tests. Some pasture herbicides carry over through the manure and the compost may not be safe to use on gardens and landscaping, so it’s important to read labels carefully.
The University of Tennessee’s Equine Extension and Research Center located in Spring Hill TN, along with three regional on-farm demonstration sites (Memphis, Franklin and Knoxville), are being developed to provide hands-on training for the equine community and to research the benefits of horse farm BMPs. To learn more about horse farm conservation and best management practices and upcoming educational events, please contact Dr. Bridgett McIntosh at email@example.com (931) 486.2777.
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