What’s That Smell?

Whether you've got five or 50 horses in your care, controlling odors in the barn is never easy. Here are some tips.

Nothing screams poor barn management louder than bad odor wafting from a horse facility. Not only will odor turn away customers, it can also lead to legal action from neighbors. Fortunately, odor can be controlled with planning and good management.

The first step to control is knowledge of what causes the odor. Two main odor producers are manure and urine. One 1000-pound horse produces an average of 31 pounds of feces and 2.4 gallons of urine a day. Add to that soiled bedding and the results are more than fifty pounds of waste per stall that has the potential to cause a stink.

Odors from the decomposition of manure arise when there is not enough oxygen mixed with the manure. (Properly composted, decomposing manure is odor-free.) Good drainage, absorbent bedding and daily cleaning will slow the odor-causing process, keeping offensive odors at a minimum in the barn.

Urine’s offensive odor is caused by ammonia. If horses are fed more protein than their body needs for bone and muscle growth, nitrogen in the form of ammonia is converted into urea. The increased urea is excreted in the urine. As a result, horses fed a high protein diet are likely to have wetter and smellier stalls. Site selection, hygiene, ventilation and waste management are the keys to controlling offensive odor generated by manure and urine.

Site Selection

In this age of urban encroachment, the horse owner has to be especially mindful of how neighbors perceive their horse facility and how the facility affects the environment. Most states now have laws regulating the management of livestock waste. Check local regulations that relate to manure handling and follow those regulations to the letter to avoid repercussions.

Common sense suggests placing barns, paddocks and manure storage bins as far away from neighboring properties as possible. Also, consider the direction of prevailing winds, especially during warm weather when odor is most apparent. For example, if the neighbors are on a downslope from the source of odor, the wind is likely to carry that odor right to their front door. Good drainage in and around the barn is important in controlling odor since dampness increases the rate of decomposition, which releases the gases that cause the odor. Barn owners can get assistance from their cooperative extension service for site selection.


Obviously, cleaning manure, urine and soiled bedding from the stalls daily goes a long way toward controlling odor. Be sure to instruct workers to remove wet bedding from under the water bucket and to take out uneaten hay as well. These areas encourage bacteria growth.

Minerals such as lime or zeolite can be spread over the wet area after urine is removed to help absorb remaining moisture and gases and to neutralize any remaining ammonia. Once the stall is dry, adding pleasant-smelling pine shavings or sawdust is a good way to hide any remaining odors. Other good bedding products are straw, peat moss, and chopped hay. Wood pellets are a new bedding product on the market that rates very high for absorbency and odor control.

Outdoors, picking up manure in paddocks and areas of the pasture where horses congregate, such as around the hay manger, gates or run-in sheds, will help cut down on offensive winds. Out in the pastures, using a manure spreader can be a source of bad odor initially, but the smell is normally gone in a few days because the manure is spread in a thin layer and works into the soil. To minimize odor, spread the manure during early morning hours before it gets hot and when the wind is low.


Horses themselves produce heat and moisture in the barn. In addition, gases from the decomposition of waste materials accumulate and cause the odors to intensify. Adequate ventilation is needed to remove the moisture and gases and control temperature in the barn. Doors and windows provide natural ventilation for those barns designed with stalls along the outside. In center-aisle style barns, however, doors at both ends of the aisle are vital to pull air through the barn. Windows and vents will also aid in natural air circulation.

Fans are usually needed—at least in warm weather—to supplement natural ventilation. Two types of fan systems can be used to circulate air in the barn. A pressure ventilation system uses fans to force fresh air into the barn, while the stale air flows out through vents. An exhaust ventilation system uses fans to pull stale air out of the barn while fresh air flows in. In either system, the number of fans and their locations depends on the barn design, number of horses, and outside air temperature. Ceiling fans, too, work well in moving the air around.

Keeping clients and neighbors happy with an odor-free facility is relatively easy and, in the end, makes your life easier.






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