Compost bedding in large open barns yields more milk production and satisfied cows

By Dan Lemke
New Ulm, Minn. — Steve and Kerry Hoffman know that a happy cow is a productive cow. Their southeast Minnesota dairy operation features a unique housing style that is not only gaining producer interest, it’s providing nearly-unrivaled cow comfort.

Called compost-bedded pack barns, these facilities employ a minimum of 18 to 20 inches of bedding, primarily fine wood shavings or sawdust spread out in large, open barns.

Twice a day, Steve or one of his hired workers pulls a field cultivator behind a skid steer over the nearly 4-foot deep pack. It’s a little extra barn management but worth the time, as the cows are more content and productive, he says.

Cows lounge on the bedding when they’re not being milked. Twice daily the pack is stirred to aerate and mix in the urine and manure. The pack aeration promotes natural composting as bacteria breaks down the manure and stabilizes it. Every three to five weeks, more bedding is added and the barn is completely cleaned once a year.

The Hoffmans became interested in the concept two years ago. They visited one of the region’s first compost barns near Sleepy Eye several times before initiating their own system in September 2004. They built a barn and increased their herd size to 93 cows.
 

“We were looking for a way to increase our cow numbers,” Steve says, but they discovered other benefits. “In the first 16 months since we’ve had this compost barn, the herd average (for milk production) has increased 4,000 pounds per cow.

“Our somatic cell count (reflecting antibody levels) also dropped,” Steve adds. Factors like stress and environment can elevate cell counts and affect milk quality. “But cow comfort was really the biggest thing for us.”

Rather than spending their days standing on cement floors, cows in compost barns lie down and eat more and in general appear more content, researchers observe. The Hoffmans have spoken with other compost-barn producers who say the soft floors decreases foot and leg problems, potentially
adding years to a cow’s productive life.

The Hoffmans’ system also simplifies manure handling and storage. With a farm perched on a hill overlooking a creek, they knew attempts to increase their herd size in other ways would meet resistance.

“We were able to increase cow numbers and combine our manure storage and cow housing into one unit,” Steve says. “Plus, there was no need for (manure) lagoon permitting.”

Kerry says she even warned neighbors last fall when they planned to spread compost on the fields, because they didn’t know how much smell it would produce. “There was none,” she says.
 

“Cow comfort is the primary reason producers consider a compost barn,” says Mindy Spiehs, a University of Minnesota extension educator in Morris, Minn., specializing in manure management systems. “Cows have fewer hoof and leg problems which allows producers to keep cows longer and build their herds. But it’s also an effective alternative manure-management system.”
 

Spiehs says compost barns are “popping up all over,” as is the interest from producers in other states and even overseas. Minnesota has become a leader in this type of livestock and manure handling system, she says.

Bedding alternatives
The Hoffmans are confident in the science behind compost barns, but face unexpected rising bedding costs. Estimated to be between 34 and 50 cents per day per cow, actual costs are about 70 cents per animal per day. Kerry sources fine sawdust from Iowa, but as wood prices rise so does the need for alternatives.

AURI, the Minnesota Soybean Growers and the University of Minnesota Extension Service are collaborating on efforts to identify other alternative bedding sources, particularly agricultural fibers.
 

“The biggest factor for expanding compost barns is finding alternative bedding,” says Spiehs. “There’s only so much sawdust available and the suppliers realize there’s a demand for it so the price goes up. The number one thing we hear from producers is ‘isn’t there anything else we can use?’”

“Straws and corn stalks generally don’t work because they pack too much and don’t provide structure for composting,” says AURI scientist Alan Doering. “But there are other fiber sources out there that may turn out to be suitable replacements.”
 

Producers have discovered that fine material works better than coarse, so AURI will source and prep optimal fibers for testing. University of Minnesota researchers will then test compost the best fibers.
 

Bedding packs that don’t compost may promote the growth of pathogens that can cause mastitis. Properly-functioning compost packs reach internal temperatures from 130 to 150 degrees Fahrenheit, killing pathogens, viruses and even insect larvae.

Doering says the project will evaluate fibers such as soybean hulls, flax straw, corn cobs, beet pulp and other materials. Tests will evaluate each bedding source for its nutrient value, water holding capacity, carbon dioxide emissions and more.

Small-scale problem
Minnesota ranks sixth in U. S. dairy production. A recent Dairy Herd Improvement Association survey found that more than 80 percent of the state’s dairy herds had fewer than 100 cows.
 

Many of these herds are in antiquated housing facilities that are too costly to modernize.

Minnesota is losing an average of two dairy farms a day. Dairy proponents are anxious to find economically-feasible solutions that allow smaller dairies to modernize their facilities. Compost barns may be one solution.

For some, the compost generated in their barns could be an additional revenue stream. Hoffman says local nurseries and landscapers have shown interest in using the compost for landscaping.
 

“I think it’s something other farmers should consider,” Steve says. “But we need to find an alternative bedding source.”

The Hoffman family.