Barn and Livestock Ventilation Systems
Dairymen are becoming more aware of the benefits of compost-bedded pack barns for cow comfort, health, and production. These potential benefits, however, will only materialize if the pack is effectively managed.
Considerations for air and light in compost-bedded pack barns
Ventilation lessons learned in compost bedded pack barns
Compost-bedded pack barns: Management and moisture tips for this type of cow facility
1. Stocking percentage
The first constraint to a good bedded pack barn is the stocking rate.
Dairymen must understand that the barn, like pasture or the feedbunk, cannot be overstocked and expected to perform. Every cow should have at least 100 square feet of laying space. Higher stocking rates generate surplus moisture, making pack management more complex and costly.
One farm's stocking rate jumped to just 75 square feet, which is far from optimal. They had to bed considerably more frequently. It was prompted by switching from free stall to a bedding pack. Cow numbers increased since they no longer cull cows due to hock or foot difficulties. Thus cow numbers grow year after year."
2. Bedding fabric
The most prevalent bedding materials in pack barns are sawdust and wood shavings. Although these materials are comparable, they behave differently since "sawdust gives considerable bulk density and is usually very dry." Because shavings have larger particles, they allow more air to enter the pack for composting."
The majority of farmers utilize a combination of both materials. The drier sawdust is ideal for keeping the pack dry in the winter.
Straw is undesirable because its waxy layer prevents moisture absorption and composting.
3. Tillage
It is critical to till the pack twice a day in order to include air into the bedding. Air encourages aerobic composting, which leads to higher warmth. Through evaporative water loss, a high pack temperature retains the bedding surface at the proper moisture level.
The farm's equipment determines "Tilling "methods. Most dairymen will till the top 8 inches with a rotavator." It is critical to till down 12 inches at least once a week. Deep tilling incorporates highly decomposed waste into the upper layers, hastening the composting process.
Steam and evaporation can frequently be seen rising from the pack during the tilling process. This evaporation produces little ammonia loss or smell.
"The ammonia is linked to the substance since the process is aerobic." Anaerobic fermentation, which does not bind ammonia, causes the ammonia odors associated with lagoons.
4. Take measurements
It is vital to measure the temperature and moisture of bedding to make educated management decisions. The composting process works best at 4 inches of depth and 55 percent moisture at 80°F.
Farmers handling a bedded pack for the first time can benefit from electronic temperature and moisture meters. After some experience, many farmers make decisions based on sight and touch.
At 55 percent moisture, the bedding should form a ball in your hand when squeezed. When you bounce it on your hand, it should fall apart. Fifty-five percent moisture allows the bacteria to compost the waste while being dry enough not to stick to the calf.
When bedding contains 60 percent moisture, it does not fall apart when bounced. This means that the bedding is too damp and requires new sawdust. If the bedding does not form a ball, the moisture content is less than 55%. This moisture level is somewhat too dry for the bacteria to function properly, yet it has no harmful impact on cows.
Additional considerations
Weather conditions will influence the management of the bedded pack. The internal temperature of the pack will drop in humid, damp, and cool weather. As a result, less evaporation occurs, and more bedding is required to maintain a moisture level of 55 percent.
Good ventilation aids in keeping the bedding pack dry. The airflow through the barn will be increased via fans and curtain sides.
A concrete alleyway should have access to feed and water. "Compost-bedded high-traffic feed locations become too muddy and difficult to handle." A 16-foot concrete feed alleyway is advised.
Leave a 6-inch base layer of compost when clearing out the barn to speed up the composting cycle during the next housing season.
Throughout the year, bedding supply can fluctuate. During the more abundant summer months, it may be essential to acquire sawdust or shavings in advance.
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