Compost Bedding Pack Barns
Table of Contents
Compost bedding pack (CBP) barns are an interesting alternative to tie-stall or free-stall housing for milking cows. A CBP barn is similar to a loose-housing barn, except the pack is managed differently. In a CBP barn, the pack area is cultivated twice per day to keep the pack aerobic and composting. Some producers consider this option a less expensive alternative to free-stall housing; others consider it for cow comfort benefits (Figure 1).
CBP barn layouts have advantages and disadvantages:
Figure 1. Compost bedding pack barns provide excellent cow comfort.
Keeping the pack composting requires careful management. Dry, dusty sawdust is the best material for bedding, as it breaks down easily during the composting process. Some producers add chopped, dry wallpaper to the sawdust to increase the absorbency and aid in the composting process. Other producers use chopped straw for bedding. The straw must be finely chopped using a bale processor. It does not compost as well as sawdust. Other materials, such as soybean straw, corn cobs and corn stalks have been tried, but sawdust is the best. Cedar sawdust will not compost.
Add new sawdust whenever the cows appear wet or bedding starts to stick to the cows. Also add bedding to any wet spot that appears in the pack. Some producers add bedding every 2 weeks to a month; some add it weekly.
Cultivate the pack twice per day to a depth of 25-30 cm (10-12 in.) (Figure 2), using a spring tooth cultivator or a chisel plow.
Figure 2.Cultivate the pack twice a day, to a depth of 25-30 cm (10-12 in.)
Table 1. Conditions for composting
Table 1 compares the preferred conditions for composting, compared to samples taken from eight different CBPs, from a study by Russelle et al., 2007.
The data collected, compared to the preferred conditions for proper composting, suggested that the pack material was not composting in the traditional sense. Even so, the researchers concluded that the heat and biological activity of the pack were sufficient to control environmental mastitis organisms and fly larvae.
Good ventilation is required in all dairy barns. Natural ventilation is usually used with many producers adding some form of supplemental ventilation to reduce heat stress. Supplemental ventilation is a must in CBP barns, as the pack gives off a tremendous amount of heat. Either basket or high-volume, low-speed (HVLS) fans can be used to reduce heat stress (Figure 3). The added ventilation also helps keep the pack dry.
Figure 3. Suppmental ventilation is necessary to cool and dry the pack.
Two types of manure are produced in CBP barns. Liquid manure is produced in the feed alley and can be handled by tractor or skid steer scrapers or by automatic alley scrapers. The CBP manure is a solid. Some producers will clean out the pack twice a year; others with limited access designs may only do it once. Never clean out the pack completely; leave some material to start the composting process when new material is added.
Composting requires nutrients, moisture and heat. Mastitis organisms also require nutrients, moisture and heat, so careful management is required to make sure the right organisms are growing and not harmful ones. Producers have experienced severe problems when they ran out of sawdust and the pack became too wet or the composting process got out of balance.
Another challenge is ensuring a steady supply of good sawdust for bedding. Wood products are also sought after for fuel, and this competition is making it more difficult to obtain good-quality sawdust in some areas.
Drawings are for illustrative purposes and are not intended for use as building plans.
Figure 4. Compost bedding pack barns can be designed to conver to free stall housing (1 ft. = 0.304m).
Cows in CBP barns are milked in either a parlour or robotically. The cow area resembles a free-stall barn with a pack replacing the free stalls. There is drive-through feeding, a feed manger, a feed alley next to the manger, then the pack. To maintain flexibility, design the barn so the pack area can be replaced with free stalls in the future (Figure 4). A pack area equivalent to the area for a 3-row free-stall barn works out well, giving each cow about 75 cm (30 in.) of manger space.
Pack Area - Design the pack to provide at least 9.5 m2 (100 ft2)/cow for Holstein cows (Figure 5). Anything less than this requires a lot more bedding to keep the cows clean and dry. More area is better, as it will improve comfort and require less bedding to keep the cows clean and comfortable. This type of housing is used by dairy producers in Israel. They use little to no bedding as the country is more arid, and they provide almost 18.5 m2 (200 ft2)/cow of pack area. Israel has the highest milk production in the world.
Figure 5. Drawing showing layout design of compost bedding pack barn.
Figure 6. Compost bedding pack barn with continuous access to feed alley (1 ft = 0.304 m).
Two methods are used to separate the feed alley from the pack.
Continuous Access - Continuous access allows the cows to move from the feed alley to the CBP at any point along the feed alley (Figures 6 and 7). This results in a drier transition area from the feed alley to the pack. It also results in a sloped front to the entire pack, which reduces the storage capacity of the pack. Roll-over or spring-loaded arm gates are used to separate the cows from the pack for cultivation or clean-out.
Figure 7. Continuous access keeps the transition between the alley and the pack drier.
Figure 8. Compost bedding pack barn with limited access to feed alley (1 ft = 0.304 m).
Limited Access - Limited access separates the feed alley and the pack with separate gated openings in a 1.2-m (4-ft) high wall. The wall allows the pack to build up evenly, resulting in more storage capacity (Figures 8 and 9). The access points will become wet and dirty if extra bedding is not added at these points.
Figure 9.Limited access allows more storage in the pack.
Waterer Location - Waterers are usually located at the edge of the feed alley next to the pack. They are protected by a wall or piping so the cows can only drink from the feed alley side. This keeps the pack drier (Figure 10).
Figure 10. Locate waterers so the pack stays dry.
Compost bedding pack barns are an interesting management alternative for dairy producers. Pack barns provide very comfortable conditions for the cow as she is free to lie down and rise as if she were on pasture. The pack is also very soft. Sawdust is the best bedding but is becoming more difficult to source as it is sought for fuel. Keeping the pack composting properly requires careful management or severe udder health problems can occur.
Barberg, A.J., M.I. Endres and K.A. Janni. 2007. Compost dairy barns in Minnesota: A descriptive study. Appl. Eng. Agric. 23:231-238.
Janni, K.A., M.I. Endres, J.K. Reneau and W.W. Schoper. 2007. Compost dairy barn layout and management recommendations. Appl. Eng. Agric. 23:97-102.
Lang, B., H.K. House, N.G. Anderson and J. Rodenburg. 2012. Free Stall Housing Manual. Ontario Ministry of Agriculture, Food and Rural Affairs. Guelph, ON.
Russelle, M., K. Blanchet and L. Everett. 2007. Characteristics and Fertilizer Value of Compost Dairy Barn Manure. Proc. of the National Compost Dairy Barn Conference. June 21 & 22, 2007. Burnsville, MN.
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