Compost dairy barns: What we learned this past winter
Published in Dairy Star April 22, 2006
Compost dairy barns continue to be a hot item on the dairy housing scene. The article in last November's Hoard's Dairyman sparked a lot of interest in dairy producers from all over the U.S. I work in two counties in south-central Minnesota that are home to four of these barns. In addition to Tom and Mark Portner who were the first to erect one of these barns in 2001, Jonathon and Steve Siefert, Mike and Judy Sellner, and Steve and Kerry Hoffman have also added these barns to their operations with mostly excellent success resulting in higher milk production and lower somatic cell counts. What is unique about these four dairy farm families is their willingness to allow other producers the opportunity to tour their facilities and ask just about any question that they can come up with.
I had the privilege to serve as coordinator and tour guide for nine of these tours this past winter. We had a total of over 375 dairy producers from 10 states and Canada participate from the month of December through March. Also included in this group were building contractors and various government agencies such as NRCS and local SWCD personnel. The informal atmosphere at these barn meetings allowed people to ask questions and get feedback from both the hosts and other farmers on the tour.
Following are some of the more interesting questions asked on the tours.
Where do I place the water drinking trough?
There has been a lot of discussion on this topic. Most of the barns have been placing the waterers along the retaining wall, usually within an indented space. The drawback, however, is that it is difficult to keep the water clean once the manure pack builds up. Tom and Mark Portner built a second compost barn last summer. They have a drive-by feeding system on the south side of the barn and placed the water troughs along the outside of the barn in the feed alley. This allows the water to remain cleaner longer and keeps the cows from putting their feet in the waterer as they sometimes did before, especially during warm weather.
How high should the outside wall be?
Experience on farms with compost dairy barns show that four feet seems to be the right height. Much taller than that risks blocking air flow through much of the barn. Lower than that allows the pack to start overflowing the wall by spring time. Current management practices call for hauling a few loads of material out of the barns in the spring before planting and doing a full cleanout in the fall. With fall cleanout, we are starting with the walls at full height for the cold time of the year when airflow is not as critical. The pack seems to build up rapidly during the winter and then seems to hold in place during the warm summer months.
A visiting producer on one of the tours asked about possibly digging the surface of the interior of the barn down a couple of feet to start with. This would probably not be a good idea because of possible water accumulation in the lower area. Another producer asked about building a shorter wall, say two feet, to save money. His situation was that he had a grazing operation and would only use the barn for six months of the year. However, because of the quick build-up during the winter time, this might not work as well as one might think. The savings in constructing a wall of less height would be offset by the need to clean out the facility more often. And, it would be more expensive to add more height later.
What is the best base under the compost area?
Many producers ask about the floor base of the barn. Should it be concrete or packed clay? Our experience shows that packed clay works very well. In fact, one of the great properties of sawdust (the bedding used) is its ability to absorb and hold liquid. Producers have told me that at cleanout they will find a clean layer of sawdust at the bottom of the compost pack that appears as fresh as the day they laid it down months before. That tells us that there is no liquid making it all the way through the pack.
What's it going to cost me to put up one of these barns?
We have been getting mixed reports on building costs. There are a lot of variables involved. Plus, there was a lot of concern after Hurricane Katrina last fall that building costs would be going through the roof. Barns built in the area in 2005 cost around $1350 to $1500 per cow space. Current projections are coming in around $1500 to $1800 per cow space depending on what's included in the price. My understanding is that the lower price includes electrical work, concrete, site prep and construction. Our best advice is to get several bids from experienced builders in your area.