Wood Pellets as an Alternative Stall Bedding Material
A Research Update by Peter Moon, P.E.
I have researched alternative stall bedding materials for horse
farms and stables with the hope of finding a product that performs
as well or better than straw or wood shavings and can be composted
to produce a superior, marketable finished compost product. In my
opinion, wood pellets achieve these goals and will soon become the
next generation in horse bedding nationwide. I am excited to pass
along some information about horse manure composting and the use
of wood pellets as an alternative bedding material.
Bedding the Stall with Wood Pellets
There are a number of ways to set up a stall with wood pellets;
however, the following series of steps seems to work quite well
in most situations:
Clean out the stall down to the floor (dirt, wood, concrete,
Place the contents of three to five bags (40-pounds each)
in the center two-thirds of the stall, and spread the pellets
out to an even depth of roughly 2 inches. Alternatively, you
may also locate the bedded area where the horse prefers to
“go”. The number of bags used will depend on the
size of the stall, climate, horses’ habits, and personal
experience from working with the bedding.
Next, lightly moisten the pellets with 2 to 3 gallons of
water to initiate their opening to a "fluffy" consistency.
(I think this is the secret to success with wood pellet bedding.)
The water serves to break down the resin sheen on the sides
of the pellet. The amount of water used will depend on the
humidity of your area and may vary at different times of the
For deeper bedding, you may choose to add one or two more
bags on top and again moisten with 1 to 2 gallons of water.
Deeper bedding is not always advantageous, and therefore some
experimentation is appropriate to optimize product use. Because
they are highly absorbent, it’s OK to be stingy with
Within 20 minutes of wetting, the bedding will expand to
approximately 3 to 4 times its original depth and it will
take on a much softer texture and a whitish color. It will
continue to “grow” somewhat over the course of
the first week.
Approximately once a week, up to 1 bag of new pellets will need
to be added to compensate for the amount of manure and saturated
bedding taken out of the stall. Note: these new pellets should
be scattered evenly and do not need to be wetted down when they
are added to the mix. Many horse owners who use pellets strip
the stalls once every two or three months, instead of weekly,
thereby saving a considerable amount of waste volume and significantly
reducing the cost of bedding and labor.
Because the solid manure separates so easily from the fine wood
fibers, very little of the bedding is actually removed from the
stall. The urine saturated areas should be removed entirely, leaving
only dry to moist bedding (Key: Do not scatter the saturated bedding,
as some brands suggest, as this will lead to ammonia odors and
necessitate mucking out the entire stall before the material has
been fully utilized).
Which Brand of Wood Pellet to Buy
Many people ask me which brand of wood pellets are best for
horse bedding, and whether a wood stove pellet can be substituted
to save on cost. Allow me to attempt to answer this question by
beginning with a brief history of wood pellet production, based
on conversations with people whom I consider to be reputable wood
pellet manufacturers in British Columbia, Canada.
Wood Pellet History
The concept of wood pellet production came about many years
ago as a way to utilize thousands of tons of waste sawdust from
the wood products industry. They were originally used as a fuel
source for large boilers and later for home owners with smaller
wood pellet stoves. The quality of wood fuel pellets is determined
in part by the moisture content (typically very low at 3 to 4%),
the BTU value, and the ash content after combustion. It is my
understanding that a wide variety of wood types are used for producing
wood fuel pellets, and that the percentages of any one type will
depend largely on availability. It is also rumored that wood stove
pellets occasionally include fine sawdust from furniture and cabinet
manufacturers as well as glues and resins used in the fiberboard
and laminate industry.
Wood pellets used for horse bedding originally involved the
same exact wood pellets as used for fuel. Because of dust problems
with many of these products, further refinement in the manufacturing
process lead a few producers to a pre-screening step to remove
the finest dust fraction.
Much of my experience with wood pellet bedding involves various
brands manufactured in British Columbia, Canada. These brands
are most frequently produced from pine sawdust, where northern
lodge pole pine is common in the wood products industry. Because
the source of pine sawdust is abundant and highly controlled,
these materials are considerably purer and more predictable than
wood stove pellets.
Wood pellets for horse bedding is a rapidly evolving industry,
with more manufacturers coming on-line each year. As high-quality
shavings become increasingly difficult to obtain, and the cost
of manure management continues to increase, I believe wood pellet
bedding will become the norm within the next few years.
Deciding Between Brands of Wood Pellets
Having said all of that, I find that the decision of the type
and brand of wood pellet to use (e.g., fuel pellet or horse bedding
pellet) is ultimately a subjective one, and should be determined
based on experimentation and personal preference. For those inclined
to research, a few telephone calls to three or four manufacturers
may help clarify the decision. Keep
in Mind... online research
(and a friendly tip) tells me that black walnut and butternut material
in stall bedding can cause laminitis or founder in horses. Therefore,
choose carefully and when in doubt, stick with pellets that have
been manufactured specifically for animal bedding.
What you will definitely experience with any brand of wood pellet
is a dramatic reduction of waste volume; often exceeding 60% to
70% when compared to shavings and considerably more when compared
to straw. This point is of key importance in developing and implementing
an effective manure management strategy. My suggestion is to try
a wide variety of wood pellets and decide which works best in
Economics of Using Wood Pellets
I also urge you (no, implore you) to not make your decision
based on product cost alone, as many other factors come into play,
including dust, moisture holding capacity, ease of handling, and
longevity. There are also many other factors to consider when
evaluating the total economics of a manure handling system, including
product availability and predictability; storage and handling;
and labor to place bedding, muck stalls and transfer waste to
the receiving area. Finally, compost produced from horse manure
and wood pellet bedding yields a far superior compost and hence
it has a higher market value.
Wood Pellets and Composting
It is important to understand that the materials going into
the compost pile predetermine the quality of the compost that
comes out of the pile. Horse manure alone (i.e., no bedding) makes
excellent compost, increases soil health and moisture holding
capacity, and stimulates plant growth. Horse manure has the correct
Carbon to Nitrogen balance (C:N), moisture content and bulk density
In the case of horse manure mixed with shavings, the initial
compost mix has a very high percentage of carbon based bedding
material and this results in high carbon compost. This often results
in nitrogen “fixing” in the soil, which can be detrimental
to plant growth. For this reason, high carbon compost is often
used as a mulch (i.e., top dressing) and generally has a lower
market value. Also, the lignin in the wood is very resistant to
decomposition, leading to the expression, “Shavings In –
With horse manure and wood pellet bedding, there is a significant
reduction in volume of wood mixed in with the manure and therefore
it is much closer to the ideal C:N ratio. In addition, the wood
particles that are in the waste are fine textured (i.e., have
a very high surface area), thereby exposing more of the wood surface
to the microbial (bacterial and fungal) activity. As a result,
the rate of composting increases dramatically and the finished
product quality is far superior to that of shavings-based compost.
I work closely with researchers at the Washington State University
Cooperative Extension Service, in Puyallup, Washington. They are
very interested in the fate of horse manure in urbanized areas,
potential impacts to surface and ground water, and benefits to
the soil when these materials are composted and used as amendments
for both food and ornamental crops. WSU recently completed a series
of laboratory tests involving raw and composted horse manure,
with both wood pellets and wood shavings used as bedding material.
The results of this investigation are summarized in the following
Mg / Kg
| Raw Wood Pellets / Manure
| Composted Pellets / Manure
| Raw Wood Shavings / Manure
| Composted Shavings / Manure
With a mix of manure and wood pellets, the Carbon to Nitrogen
ratio (C:N) of the finished product is below 20:1, and as such
the nutrients contained in the compost will be released to the
soil and plants. In the case of shavings / manure mix, the C:N
is nearly 70:1, and in this case nutrients will be drawn from
the soil to continue the decomposition of the wood fraction. This
latter condition is clearly disadvantageous in every regard.
It should be noted that in both cases the compost tested was
produced using the aerated static pile method, which induces airflow
through the mix of materials to maintain aerobic conditions throughout
the pile and enhance microbial activity. By maintaining aerobic
conditions, odors were controlled, pathogens and weed seeds were
destroyed, and the composting process was expedited. In both cases,
the material was handled just twice: the first time to place the
waste into the aerated bin or bay and the second time to remove
it again and load it out for final use.
I have provided an alphabetical list of links to wood pellet
manufacturers. This is not a comprehensive list, and I would be
interested to learn of any other brands that can also be included.
Please send them to me if you come across other brands, and I
will add them to the list.
Decide for Yourself
The best way to determine whether wood pellets are a suitable
and economic choice for your stable is to conduct two quick and
Experiment #1 – Bench Scale
Place 1 cup of your bedding material (tightly compacted)
in a one-gallon size zip lock bag.
Place 1 cup of any wood pellet product (horse bedding or
fuel) in a second one-gallon size zip lock bag.
Add 1 cup of water to each of the bags, seal and observe
continuously for 5 minutes and then again at the end of 30
minutes. I believe that you will be amazed at the difference
Experiment #2 – Stall Scale
Select two stalls, one with a horse that has "good
manners" and one with a horse that is "a pig".
For two weeks, use your current bedding material in these
two stalls and muck them out in your normal fashion. During
this time, estimate the volume of waste material that comes
out of these two stalls (i.e., how full is the wheelbarrow,
or how many wheelbarrows?) and monitor how long it takes to
do a thorough job.
Next, strip both of these stalls down to the rubber mats
and set them up with wood pellets, as described at the top
of this discussion. Use a wood pellet product of your choice
(i.e., fuel pellet or horse bedding pellet). I have found
that the brand of wood pellet is a matter of availability
and personal preference.
During the next two weeks, clean the two stalls out with
a manure fork (apple picker) to pick up the solids and a square
nosed shovel to collect the urine-saturated areas. This may
require some practice, but this will come in handy later when
you instruct the stall cleaner how to avoid over-cleaning
the fresh bedding materials. As before, estimate the volume
of waste material generated and monitor how long it takes
to do a thorough job.
Compare the total volumes and times at the end of the one-month
trial. Use these numbers to project the total volume reduction
and time savings for your total operation.
Lastly, give me a call and let me know how it worked out
for you. The information that you derive from this experiment
will serve as the basis for sizing an aerated compost system
appropriate for your farm or stable, and I may include the
data on this page at some future date.
It is important for you to know that I am not a "horse person"
as such. I’ve been around horses for years, but most people
introduce me by saying, "I’d like you to meet Peter
Moon - he’s the manure guy that I was telling you about".
In terms of wood pellet quality, I rely on other people’s
experience and opinions (and sales pitches), and I have tried
to pass along only the most credible information. In terms of
the manure (i.e., the raw materials that go into the compost pile
and the finished compost that comes back out), you can count on
me for a well informed appraisal.
I do not market or endorse any particular brand of wood pellets.
My goal is to minimize the amount of carbon that goes into the
compost pile, regardless of the bedding type. Zero bedding is
preferred overall. Further, I am interested in helping stable
owners minimize the cost of their manure management obligation.
My ultimate goal is to help horse owners realize a positive return
on their investment in my compost systems, and to develop a new
profit center for their business, farm or stable.
Thank you for the opportunity to provide this information on
the benefits of composting horse manure and wood pellet bedding.
I believe that this is a higher and better use of these materials
and represents a “Full-Cycle / Recycle” opportunity.
It also provides the horse owner / stable manager the possibility
of decreasing expenses and creating a profit center for the farm.
For further information, please refer to Training
Programs or call me at 360-568-8085.
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