A compost bedded pack barn (CBP) is a type of housing for dairy cattle. It is a loose housing system, similar to free-stall housing, except there are no stalls or partitions.^[1][2]

In a CBP, the resting and exercise areas of the cows are combined, resulting in reduced ammonia emissions, lower building costs, and increased cow movement.^[1] For these systems to be successful, they must be managed very closely. They require tilling with a roto-tiller or deep-tillage tool to incorporate the manure, urine, and air into the pack and allow it to dry.^[1] The composting process allows the manure and urine to be stored for months at a time, while also supplying a bedding and exercise area for cows.^[1]

Compost bedded pack barns are a fairly new system for housing dairy cattle, and are appealing to producers due to the lower instances of lameness and hock lesions.^[3] They also improve cow comfort, as the cows are not restricted in their lying behavior from stall size and partitions that are typically found in free-stall housing systems.^[3]

Compost bedded pack barns are typically bedded with wood shavings/sawdust, or other organic materials that are compostable.^[3]

For the composting process to work in a CBP, the internal temperature of the pack must be maintained at approximately 43.3–65.0 °C (109.9–149.0 °F) and have a moisture content at approximately 40–60%.^[1] The lower end of the temperature range is compatible with cellulose degradation, which is needed to break down the wood shavings/sawdust that is typically used.^[4] The higher end of the temperature range is compatible with pathogen destruction, which helps destroy mastitis-causing bacteria.^[4]

The first CBP in the US was built in 2001 in Minnesota.^[3] However, the compost bedded pack system was invented by dairy farmers in Virginia to improve upon the conventional bedded pack system.^[4]

The recommended stocking density of a CBP is 7.4 m²/cow (80 sq. feet/cow) for the average Holstein cow.^[4] This allows for the proper aeration and absorption of manure and urine by the bedding and still allow the composting process to work.^[4]