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.
Reuse of horse bedding = Cost and health benefits
The viability of composted stable waste re-used as bedding for horses has financial benefits by saving on the cost of material purchased, disposal of stable waste, and further savings in health care costs.
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.
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 in Snohomish Washington for the Snohomish Extension Service and Washington State University 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.
Dr. Mueller 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 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.