Thinking About a Compost Bedding Pack?
Posted: December 19, 2011
The rules don’t change! Every dairy shelter, no matter the style, needs to provide the cow with a clean, dry, and comfortable resting area, good ventilation, and ready access to high-quality water and feed. How you plan to provide it is where we begin our discussion.
Figure 1: Typical layout of a compost bedded pack
How to build one . . .
Space is the number one design concern with a compost bedded pack barn. A minimum of 100 ft2 per head of bedded/compost resting area should be provided for lactating cows. Remember that the resting area does not include the scrape alley.
The scrape alley is normally located between the resting area and the feed area. Proper cleaning of this scrape alley is important to maintaining the pack. Twice daily removal of the manure and urine deposited along the feed bunk keeps the pack much drier. The scrape alley should be properly grooved to provide good traction for the animals.
A feed area for a compost bedded pack should be built the same as any other barn. The feed should be presented at 2 to 6 inches above the cows’ front feet to encourage a head down grazing position during eating. The feed table should be a smooth, hard, easily maintained surface to promote maximum dry matter intake.
Proper placement of waterers is critical in maintaining a dry pack area. Waterers should be located along the scrape alley with access limited so cows must stand on the scrape alley to drink. This will help limit the amount of water that is spilled onto the pack and also stops cattle from trampling the pack around the waterer.
Keeping cows cool . .
Cows get hot even in pack barns. As a minimum, circulation fans or high volume-low speed fans should be located over the pack area. Placing sprinklers and fans at the feed area should also be considered for additional cooling. More frequent cleaning of the compost pack should be considered during the summer to remove the heat load added by the bacterial action in the pack itself.
Ventilation is another important aspect. Providing good, natural ventilation requires high, open sidewalls to promote air exchange. Ventilation can be controlled with the use of a sidewall curtain. Open end walls are also recommended.
Like other barns, animal handling is an important design criteria. End wall doors and possibly sidewall doors must be placed to allow easy cleanout of the pack. The lower wall sections need to be either concrete or wood plank to both contain the pack and provide a “buck” wall during cleaning. Limiting access between the pack area and the feed area to only a few places will allow easier movement of the herd, especially during scraping, bedding, and cleanout.
Space, bedding costs money . .
First, if you are considering building a compost bedded pack barn to save on construction costs, I’d suggest you take a closer look with a sharp pencil in hand. While a compost bedded pack barn may mean less concrete and less equipment than a free stall barn, the building itself will need to be larger. So, because you buy a building by the square foot, the bedded pack may give no capital advantage. Table 1 shows the space needed to house 80 cows with five different housing types; two-row head-to-head and tail-to-tail freestalls, a three-row freestall, and two different compost pack shelters.
Table 1. Comparison of housing types for an 80 cow herd
|Housing Type||Building Size||Square Footage||Feed Space per
Space per Cow
|Three Row Freestall (81
|140 ft x 52 ft||7,280 ft2||20 inches||89 ft2|
|Two Row tail-tail
Freestall (80 stalls)
|184 ft x 44 ft||8,096 ft2||25 inches||101 ft2|
|Two Row head-head
Freestall (80 stalls)
|208 ft x 42 ft||8,736 ft2||31 inches||109 ft2|
|Bedded Pack *||160 ft x 65 ft||10,400 ft2||24 inches||130 ft2|
|Bedded Pack †||216 ft x 52 ft||11,232 ft2||32 inches||140 ft2|
* based on 2 ft of feed space and 100 ft2 of resting area per cow
† based on building width of 3 row freestall shelter and 100 ft2 of resting area per cow
From the numbers in Table 1, if you are building a compost pack barn, the shelter will need to be 40 to 55 percent bigger than a three-row barn to house the same 80 cows. If we assume the extra space can be built for $10 per square foot, you would need to save $30,000 to $40,000 in stalls and concrete just to break even in capital expenses.
When looking at the economics of packs versus free stalls, bedding must be considered. That’s both the cost of bedding and its availability. In some regions, organic beddings such as sawdust and shavings are becoming more expensive and harder to find, particularly in the winter months. A small rise of 25 cents per cow per day in bedding costs becomes $7,300 for the year in our 80-cow herd.
While no real exact numbers exist on bedding usage, the estimated usage would be 10 to 15 pounds of bedding per cow per day on a compost bedded pack and 5 to 10 pounds per cow per day in a freestall. The actual bedding use will depend greatly on the exact design and management of either housing system. This may translate into a three-to four-fold increase in bedding usage for a compost bedded pack barn. Given the large need for bedding it is often recommended that a bedding storage structure be considered to be able to stockpile bedding during times of the year when it is available.
More flexibility . . .
Compost bedded pack shelter do have some advantages in many areas. With more space per cow they allow more freedom of movement for the cows, and may provide better cow comfort. Because cows spend less time on concrete, you may see better foot and leg health. The footing is better, especially for lame and injured animals. Likewise, cattle may show more active estrus behavior. Compost packs also afford more flexibility to house animals of different breeds and sizes. Finally, the additional space per cow leads to more air volume per cow within the shelter and perhaps better ventilation and easier cooling in the hot weather.
Above all management is the key to providing good cow comfort with a pack barn. First, the pack must be groomed at least daily. Many producers are dragging or tilling the pack in order to incorporate the manure with the bedding before adding a fresh layer of bedding. The purpose of dragging is to accelerate the drying of the pack and minimize wet spots. If maintenance is not performed on a regular schedule, the perfect environment for mastitis has been created where the bugs have water, food, heat, and a home.
The final word . .
One bit of advice I often give when building a compost bedded pack barn is to use building dimensions that would easily allow you to convert to freestalls at a later date, if desired. As with all dairy housing design, building with flexibility in mind is always a good idea.
- By John Tyson, Penn State Extension educator, Mifflin County