To examine the financial, operational and health benefits of re-using composted bedding in the equine industry.
Stable waste, consisting of manure, urine and wood shavings, is a readily compostable feedstock that generates heat and can be transformed into finished homogenous compost, which can be used as bedding for horses and other livestock. This transformation can be completed in as little as 2 weeks with in-vessel technologies, 15-25 days in aerated site-built systems and 20-30 days in aerated static pile (ASP) systems. If composting is done in a biologically active, aerobic environment such as the systems mentioned above, the process destroys weed seed, parasites and harmful pathogens. These benefits are the result of system controls such as a correct ratio of C:N, moisture, porosity of the pile, and temperature. The in-vessel composting system offers the most comprehensive control of these factors ensuring the most favorable results.
The biological process that occurs when the stable waste is blended utilizes the leachable N and binds it in the organic matrix keeping it secured. There is also a reduction in N during the process as it becomes volatile and escapes through vaporization. The phosphorus is utilized by the bacteria during the process, reducing the amount available to leach by at least 50%. Since both N and Ph are needed for cellular growth, they get locked in the cells of the growing bacteria. This process generates heat, removing the moisture, killing pathogens and creating drier and more absorbent material for bedding re-use.
IOS Ranch, a private 20 horse show stable on Bainbridge Island, Washington, was the study site for this paper. They purchased an Earth Flow in vessel system and it is from this system that the lab results and observational data were collected. Their bedding of choice is medium sized bulk shavings. Also studied over the same period of time was the Earth Flow in-vessel system at Joint Base Myers/Henderson in Arlington, Virginia. The US Army Caisson horses stabled there are bedded on pelletized bedding. Lab data from this composting mix contributed to this study as well.
Washington State University, encouraged by the potential of financial savings, started using composted material as bedding in the school’s dairy farm. An unexpected benefit of this decision was the reduction of mastitis in the dairy herd. The change in bedding was the only variable altered in the care of the herd when this observation was noted. A study conducted by Cornell University’s Waste Management Institute studied the financial effects of using manure solids (DMS) as bedding. This study showed an average of $37,000 was saved annually by the diary farms who switched to re-use bedding. It was from these observations that we decided to apply the same questions to the equine industry.
A study conducted by Caitlin Price Youngquist of the Snohomish Conservation District, and funded by Western SARE is searching for the health benefits to horses with the use of composted stable waste as bedding. Preliminary examination has shown an increase in foot and leg health and a decrease in thrush, scratches and dermatitis seen on the horses in the study. General foot and leg health was also attributed to compost bedding by Dr. Hannah Mueller of Cedarbrook Veterinary Clinic and Northwest Equine Stewardship Center. She documented relief for a horse with chronic hives and a horse with a tracheotomy. The reduction of dust has been cited as a benefit to the horses suffering from heaves and other dust related ailments such as skin and respiratory irritations. The compost material has the unique quality of a large capacity for absorption while at an already higher level of moisture that makes the compost bedding less dusty. Both pellets and shavings exhibit this attribute.Youngquist’s assumption for the benefit composted bedding offers is based in the process itself. She states, “The compost has been through a very hot phase to kill all pathogens and parasites. It now has a thriving microbial population that competes aggressively with the fungal and bacterial pathogens that cause infections and irritations on skin and hooves (similar to the concept of a pro-biotic).”
Stable waste compost as bedding can be used in its entirety or screened to collect the larger remaining pieces of shavings for bedding, leaving the fines for soil amendment. Testing has shown in either case the composted material to have high absorbency, more so than green shavings. When mixed with 50% new or green shavings, the stall is at its most efficient for health and comfort for the horse. The composted material offers higher absorption, soaking up the urine off the stall floor. With a top dressing of new shavings the stall is aesthetically pleasing to the human eye, light in color and offering the horse a barrier to the wetter, compost material below. The compost bedding is odor free when reintroduced to the stall. The introduction of at least 50% new shavings also supports the ongoing composting system, refilling the system when it has its 40-50% reduction of volume and the eventual breakdown of the shaving pieces with multiple trips through the system. Continuing research is being done to understand the effect of pelletized bedding used in the bedding re-use loop without the introduction of a larger substance to affect the integrity of the material as it continues to be re –used.
The first test done was to measure the absorption ability of the three types of bedding mixes. Two inches of material was placed in a plastic container. The first test done on 2” of green shavings, the second test done on 2” of a 50/50 mix of green shavings and compost, and the third test done on 2” of compost. Each of the variations was weighed before the introduction of water. One gallon of water was poured over the material and allowed to stand for 2 minutes. The container was then drained of any standing water which was measured. The container was again weighed in each case after the water had been drained. This procedure allowed for the measurement of absorption by both the increase in weight and the volume of water not absorbed by the material.
The new shavings taken from a loose pile absorbed the least, the 50/50 mix the next higher amount and the compost bedding absorbed the most moisture. This is impressive when one considers that the density of compost bedding is higher before the introduction of the test water. The compost material is comprised of the same woody fiber as the shavings but the edges have softened and loosened, and it is possible that the breakdown of the resins, which can be hydro phobic, allows for additional absorption ability.
We also tested for the moisture content of each bedding type with a simple oven test. The material was measured by a two cup measuring cup and poured into a glass baking dish. The material was weighed before going into the oven, set at 200°. The material was then weighed again to determine the moisture content after 12 hours.
These preliminary tests were performed to study initial benefits noted with bedding re-use. These are not scientific studies and are only intended to show possible indications for the purpose of this paper and to encourage further study. With composting and bedding re-use, barns close the waste stream loop and create a value added product.
The viability of composted stable waste to be re-used as bedding is proven to provide financial benefits by saving on the cost of material purchase and in the disposal of stable waste. It provides further savings in health care costs.
Laboratory Results for Composted Stable Waste
We will continue to support the Snohomish Conservation District study run by Caitlin Youngquist by supplying composted stable waste and collaboration.
We plan to run our dust measurement during the summer months when we actually have dust in the Pacific Northwest. A furnace filter attached to the intake side of an 18” x 18” fan would be left on at ground level in a newly bedded stall for three minutes while the horse was hand walked around the stall. This would be repeated for the three bedding variations. The filter would be weighed before being attached to the fan and again after the three minute period.
Study of pellets as bedding re-use material will be done, measuring the health benefits and the viability of the product over multiple uses.
A controlled trial on direct contact allergens will be conducted on the three bedding mixtures.
We will continue to educate the equine industry and encourage a broad scale adoption of this closed waste system.
Mollie Bogardus, MBA Sustainable Business, Equine Specialist, Green Mountain Technologies, Inc. and Michael Bryon Brown, President, Green Mountain Technologies, Inc.
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Cohen, Jamie. "Composted Horse Manure: The Pros and Cons." The Florida Horse Feb. 2013: 23. Print.
"Equine Applications." Green Mountain Technologies- lab results. N.p., 12 Dec. 2012. Web. 1 Mar. 2013. <http://compostingtechnology.com/equine>.
LeaMaster, Brad, James R. Hollyer, and Jennifer L. Sullivan. "Composted Animal Manures: Precautions and Processing." Cooperative Extension Service,College of Tropical Agriculture and Human Resources, University of Hawaiâ€˜i. University of Hawaii at Manoa, n.d. Web. 6 Mar. 2013. <http://www.ctahr.hawaii.edu/oc/freepubs>.
Price Youngquist, Caitlin. "Composted Horse Manure and Stall Bedding Pilot Project - YouTube." YouTube. Snohomish Conservation District, 17 Jan. 2013. Web. 1 Mar. 2013. <http://youtu.be/B91U5UjuaXI>.
Schwartz, Mary, Jean Bonhotal, and A. Edward Stachr. "Use of Dried Manure Solids as Bedding for Dairy Cows." Cornell Waste Management Institute. Cornell University, n.d. Web. 1 Oct. 2012. <http://cwmi.css.cornell.edu>.
Wheeler, Eileen , and Jennifer Smith Zajaczkowski. "Horse Stable Manure Management." Cornell Cooperative Extension, Orange County Equine, Saratoga County Equine. Penn State University, n.d. Web. 6 Mar. 2013. <http://cceequine.org>.
Zaborski, Ed. "Composting to Reduce Weed Seeds and Plant Pathogens - eXtension." eXtension - Objective. Research-based. Credible.. University of Illinois at Urbana Champaign, 22 Oct. 2012. Web. 2 Oct. 2012. <http://www.extension.org/pages/28585/composting-to-reduce-weed-seeds-and....
This report could not have been done without the support of Philippe Le Dorze at IOS Ranch. His interest and pursuit of knowledge pushed us to continue to search for improvements and greater knowledge.
The staff at Joint Base Myer/Henderson, Amy Fagan especially, were also willing participants in the pursuit of the perfect compost recipe. Paul Brezovec at Concurrent Technologies Corp was a tremendous support to the project and continues to encourage the use of Earth Flow vessels for other bases.
A special thanks to Caitlin Price Youngquist for her ongoing dedication, collaboration and interest in the phenomena of bedding re-use.
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