Composted Horse Manure and Stall Bedding Pilot Project

The Snohomish Conservation District (SCD) worked with ten commercial and two private barns during the course of this project. Collaboration with large and small facilities allowed us to test composted bedding in different environments and under a variety of management styles. For the purpose of this report, equine facilities are referred to as “barns” and owners or managers are referred to as “managers.”

Five micro-bin composters (http://www.o2compost.com/content/MicroBin.htm) were purchased from O2 Compost in Snohomish, WA. In addition, two Stall Sh*fters (R) were purchased from Brockwood Farm in Nashville, IN (http://www.brockwoodfarm.com). Eight barns participated in this initial phase, seven of which used the MicroBin system. The first compost micro-bin for this project was set up on May 18, 2011. The basic steps of this process are illustrated below.

1. Assemble MicroBin on-site (A) and fill with manure and bedding (B).
   Turn on the blower to provide aeration (C) and monitor temperatures.
   After 30 days of composting, empty the bin (D) and sort the composted manure from the bedding using the Stall Sh*fter (E).
   Use the composted bedding in the stall (F) and composted manure in the garden (G).

Snika Farms is a mid-sized boarding and training facility near Snohomish. The stalls are bedded generously with wood pellets, and we were able to recover about 50% of the compost as reusable bedding. In our assessment, this compost made very effective bedding when blended with fresh wood pellets. The moisture in the compost eliminated the need for additional water to make the wood pellets expand, while the wood pellets "brightened" the composted bedding in the stall. The manager did not like the dark color because the stalls were already dark (low lighting and dark paneling) and did not want to spend the extra effort managing a different type of bedding.

Paramount Equestrian is a large horse boarding and training facility near Arlington. This facility was recently sold, but at the time of this trial all stalls were bedded very heavily with wood shavings. By volume, over 80% of the stall waste was bedding and the remainder was manure. Through this project, we were able to show the farm owner how much bedding was being wasted because of stall management practices. He then worked with his employees to reduce the quantity of discarded bedding. Because of the high proportion of wood shavings, this compost made great bedding. It was still slightly damp after composting, but this reduced dust in the stall. The owner was happy to try it in a few of his stalls, but reported that clients often asked about the "dirty stalls." It was also difficult to convince him that the compost should be used in the stalls and not around his landscaping - it was a beautiful product!

Macomber Farm raises beef cattle and boards a few horses in Granite Falls. Their stalls are bedded conservatively with wood pellets, and they found the compost was too wet to be practical for bedding and used it for landscaping instead. Note how dark this compost is compared to the compost from Paramount Equestrian. This is due to the much higher ratio of manure to bedding, and wood pellets instead of wood shavings.

Top Fox Farms is a large boarding and training facility near Snohomish. Their composted bedding was also a great product (similar to Paramount Equestrian) and very practical for use in the stall. However, the manager felt it was too dark in color and looked "dirty." Before starting this project they had the manure regularly hauled off-site by a local shaving supply company. After participating in this project the owners became very proactive about composting and reducing their disposal costs. However, they could not make the leap to using the composted bedding in the stalls.

Mission Farrier School is located near Snohomish and operates a large boarding facility as well as a farrier school. The MFS is very conservative in their use of shavings, and this greatly reduced the re-use value of their compost. Although they appreciated the concept and supported the project, the composted bedding was too wet to be practical and the quantity recovered was very low, similar to Macomber Farm.

The Northwest Equine Stewardship Center (NWESC) is an equine rescue organization that works with Cedarbrook Veterinary Care (CVC) in the Monroe area. They are generous in their use of wood pellets for bedding (similar to Snika Farms). As a result, they recovered about 50% of the compost as reusable bedding. They found that the composted bedding was very effective when mixed 1:1 with wood pellets in the stall. The extra moisture in the compost eliminated the need to add water to the wood pellets and minimized dust in the stall. Dr. Hannah Muler of CVC noticed a distinct improvement in one of the rescue horses during this trial. The horse had recently received a tracheotomy and showed reduced skin and respiratory irritations while bedded with compost.

Rebecca Potter operates a mid-sized horse boarding facility and beds the stalls with wood pellets. After making one batch of composted bedding she found that the compost was too wet and was not practical as bedding.

The Leung Family keeps two horses at their home. They had previously designed and constructed a large aerated compost system for horse manure and were intrigued by this project. They borrowed the Stall Sh*fter to experiment with composted bedding on their own. While they appreciated the concept of recycled bedding, and that it was less dusty than wood pellets, they did not like how dark it was and felt that it was "more labor intensive than the positive outcome warranted."

In June, 2012, we connected with a private company, Green Mountain Technologies (GMT), that designs and builds in-vessel composting systems on Bainbridge Island, WA. Completely independently of this Western SARE-funded project, they had also begun experimenting with compost as a stall bedding material. Their Earth Flow system uses a mechanical auger to break-up the manure and highly-controlled air flow to regulate temperature and moisture. This system allows for 100% resource recovery because there is no need to remove manure - it just gets incorporated into the final product. The result is very consistent and high quality bedding.

By delivering composted bedding (produced by the Earth Flow at Ios Ranch) directly to farms, we were able to increase the number of farms participating in the trial and eliminate variation between farms. At this point we were getting very curious about the possible health improvements reported in two separate barns in completely independent trials (NWESC and Ios Ranch). We sought out horses with hoof, skin or respiratory irritations with the intention of gaining more anecdotal evidence of the benefits of composted bedding.

Based on what we observed throughout the course of this project, the reported health improvements are likely due to one or more of the following factors:

1.The composted bedding is much less dusty, which can reduce respiratory irritations.
2.The composted bedding has a near a near neutral pH and, therefore, is less acidic than shavings or sawdust.
3.Compost has a thriving non-pathogenic microbial population that creates a very competitive environment. This is not conducive to fungal or bacterial skin and hoof infections such as scabs, rain rot or thrush.

While horse health is not the primary interest of the Snohomish Conservation District, nor the focus of this project, it is very important to horse owners. Highlighting the potential horse health benefits of composted bedding serves two purposes. First, it increases the interest in using composted bedding. Horse or barn owners who were not otherwise inclined to spend the time and effort to participate in a trial were willing to try compost with the hope that it would help horses with a skin or respiratory condition. And second, gathering sufficient anecdotal evidence about horse health would help justify a clinical trial. If a clinical trial were to show that composted bedding was beneficial, or at least not risky, it would contribute greatly to the acceptance of compost as a stall bedding material.

Edensgate Farm is a small horse boarding facility in Monroe that beds stalls very conservatively with wood pellets. They used composted bedding in the stalls of several horses for about a month and showed positive results in terms of both stall management and horse health. In the words of Julie Boulter, owner and manager:

"I have had some interesting results from using the composted bedding. I am putting it in the general area where my horses tend to pee and poop anyway. It does a better job absorbing, even though my compost is really heavy at the moment from all the rain. Two of my three horses have become very specific about where they go in the stall when I use the compost and will ONLY go in that area when it is there. If I don't use it they tend to get messier again! The result is that (I think) I am using less bedding because I pretty much only need to remove the area where the compost is."

After three weeks of using the composted bedding, one horse showed a distinct improvement and the rain-rot scabs had started to go away:

After three weeks of using the composted bedding, one horse showed a distinct improvement and the rain-rot scabs had started to go away:

"Dolce is doing much better, probably 75% improvement. Aside from a stray scab or two, her back and belly is all cleared up. She still has two stubborn spots on either flank, but the scabs there are smaller now, and the area it covers is much less than when we started, so I am hopeful it will go away."

Holly Farm is a large boarding and training facility in Bothell, home to Equine Life Solutions. They used composted bedding (three parts wood pellets to one part compost) in one stall for seven days. They were happy with the compost and found they used less bedding because it was so absorbent. The composted bedding was used for a horse with a severe case of sweet-itch, and they did not notice any changes in his condition during this week. They look forward to continuing to experiment with composted bedding and use it in more stalls.

Liberty Bell Stables is a mid-sized horse boarding facility in Snohomish. They bed stalls with a moderate amount of wood shavings (less than Parmount Equestrian or Top Fox Farms). The owner used a composted bedding mixture for several weeks for her personal horse with a bad thrush infection in his hooves. She found that the 1:1 mixture worked well and did not affect the amount of time to clean the stall, the total amount of bedding used, or horse behavior. In her words, "He had thrush when I started and didn't when I stopped."

Lynn Gross owns several horses and keeps them at their home in Stanwood. At the time of this trial they were bedding stalls generously with wood pellets (similarly to NWESC). They used composted bedding for a week and had similar observations to many other participants. They found that it was harder to see the smaller pieces of manure and separate them from the bedding, and the dark color made it feel as if the stalls were not quite clean. There were not horse health concerns at the start of this trial, and no effects were observed. In her words: "If this product were used on the same farm it came from and the health of the animals was known, then I think this is a fabulous idea. The cost savings would likely be considerable."

• B: Fill with manure and bedding
• C: Turn on the blower to provide aeration
• D: After 30 days of composting, empty the bin
• E: Sort the composted manure from the bedding using the Stall Sh*fter
• Composted bedding at Snika Farms after screening with the Stall Shifter
• Dirty stall bedding before composting (left) and finished compost before screening (right) at Paramount Equestrian.
• A: Assemble Micro Bin on-site
• F: Use the composted bedding in the stall
• G: And the manure in the garden
• Composted bedding at Macomber Farm before sorting (left) and after screening (right).
• Composted bedding made with the Earth Flow system.
• Composted bedding ready for use in the stalls (left) and manure ready for the garden (right) at Paramount Equestrian.
• Composted bedding (left) and manure (right) at Top Fox Farms.
• Finished compost at Mission Farrier School before (left) and after screening (right).
• Finished compost before (left) and after screening (right) at NWESC.
• The Earth Flow compost system located at Ios Ranch on Bainbridge Island.