Compost-bedded pack barns are a relatively new housing system of interest globally.

At the 2015 European Federation of Animal Science meeting in Warsaw, Poland, scientists representing the U.S., the Netherlands, Belgium, Germany and Austria presented research in compost-bedded pack barns from their respective countries.

University of Kentucky researchers Joe Taraba, Jeffrey Bewley and Elizabeth Eckelkamp discussed compost-bedded pack barns in Kentucky, stating that well-managed compost-bedded pack barns can provide the following benefits:

• A comfortable resting surface
• Ease of lying and rising
• Allow animals to express more natural behaviors
• Easily house different sizes and breeds of animals

However, challenges of this system include:

• The highly variable bedding cost
• Difficulty finding available bedding
• Increased building footprint relative to freestall or tiestall housing

An additional use of compost-bedded pack barns is as an alternative manure management system. Because compost-bedded pack barns can store manure for a long period of time, they can allow flexibility in utilization of nutrients. Composting may also allow for increased concentration of nutrients when material is land-applied.

Compost-bedded pack barns also provide a healthy environment for dairy cattle. According to Kentucky research, udder health among cows housed in compost-bedded pack barns was not significantly different from cows housed in sand-bedded freestall barns.

Take-home message: Compost-bedded pack barns are a viable housing option for dairy cattle. Just keep an eye out for bedding availability and pricing.

Ammonia emissions

Researchers from the Netherlands discussed ammonia emissions from compost-bedded pack barns. Compost barns in the Netherlands typically use pre-composted bedding, which is typically waste from the food industry. This material has been suggested to have spore-forming bacteria populations that can persist in pasteurized milk.

However, good results have been seen with improved animal health and welfare when composting with wood chips, sawdust and peat, like the bedded pack barns in the U.S. Another system involving sand-bedded packs has also been used in the Netherlands.

Although no composting can occur, it still provides an open resting area for dairy cattle. It needs to be groomed daily to maintain a clean resting surface.

Pre-composted material also had higher ammonia and carbon dioxide emissions than composting with wood byproducts. In the Netherlands, where greenhouse gases are monitored, lower ammonia emissions are a benefit from these barns.

Dutch researchers also noted that the nitrogen losses (ammonia emissions) increased at a lower carbon-to-nitrogen ratio. This would occur more in the pre-composted material than in a high carbon source, like wood byproducts.

Take-home message: Compost-bedded pack barns can have excellent animal health and welfare with decreased ammonia and carbon dioxide emissions when wood byproducts are used. However, pre-composted material may increase emissions when used as compost-bedded pack bedding material.

Other countries

Austrian researchers evaluated the use of compost-bedded pack barns for Austrian dairy farmers. They found cow hygiene was excellent in these barns, housing between 18 and 35 cows per farm. The dirtiest part of the cow was the lower leg, while the cleanest was the udder.

Researchers also noted lower levels of lameness, hairless patches and joint injuries in compost-bedded pack barns compared to cows housed in straw-bedded freestalls.

A German research team analyzed the air flow pattern through different barn designs and ridge vents. They found that barns with closed ridge vents trapped air inside the barn, limiting air exchange, even with strong blowing winds.

However, barns with open ridge vents allowed the air to mix throughout the barn and escape through the open ridge. This allowed a higher rate of air exchange, which may lead to healthier animals when housed in these conditions.

Take-home message: Barns with closed ridge vents actually prevent air exchange from occurring effectively. Austrian farmers had similar experiences to Kentucky farmers with compost-bedded pack barns.

They experienced animals with good cleanliness and low levels of lameness, hairless patches and joint injuries.  PD

PHOTO: Research from around the world shows compost-bedded pack barns are a viable housing option for dairy cattle. Photo by Elizabeth Eckelkamp.

Elizabeth Eckelkamp is a graduate research assistant with University of Kentucky. Email Elizabeth Eckelkamp.

Jeffrey Bewley is a dairy extension specialist at University of Kentucky with a master’s degree from University of Wisconsin – Madison and a Ph.D. from Purdue University.