Marcia Endres
University of Minnesota
Compost dairy barns offer an alternative to handling dairy manure as a solid rather than a liquid. Although often compared to older bedded pack systems, the compost dairy barns have two significant modifications: 1) use of sawdust as bedding and 2) increased ventilation. Although the barn designs vary, they share several features, including bedded pack on a clay base, 4-foot perimeter wall surrounding the pack, two or more walkways for cows and equipment to enter the pack from the feed alley. Water troughs are in different locations but designed to keep water away from the pack. The concrete feed alleys may be in the center or outside lane and are scraped twice each day. Management of the pack includes maintaining a depth of 4 feet of sawdust or fine wood shavings, with additions every 2-5 weeks, and aerating the top 8-10 inches twice daily. The bedding is removed yearly, usually in the fall, and land applied or further composted.
A 2005 University of Minnesota field study evaluated the impact of the 12 different compost barns on cow comfort, health and performance. Although the top layer of pack was biologically active, the temperatures were elevated only slightly, indicating minimal composting activity. Somatic cell counts in milk were highly variable between farms but compared favorably to the Dairy Herd Improvement Association (DHIA). Mastitis infection rates dropped significantly for 6 of the 9 herds that changed from traditional facilities to the compost barn. Researchers noted that excellent cow prep at milking time, management of the barn and cow cleanliness are key to maintaining good milk quality and udder health. The average pack area per cow in the study (90.2 sq-ft) was higher than the recommended 80-85 sq-ft/cow and possibly had a positive effect on cow social behavior. In addition, the prevalence of hock lesions and lameness was lower than in other systems. In general, the producers were satisfied with the system, including reduced management time, with the only concerns being the dust when replacing the pack and the cost and availability of sawdust for bedding. A pilot study is underway to evaluate the effectiveness of other materials as bedding options.
Additional Resources:
PowerPoint slides from presentation:
http://www.oardc.ohio-state.edu/ocamm/OCAMM_endress07.pdf
UMN website: http://www.extension.umn.edu/dairy/management/compostbarns.htm
UMN Compost Bedded Pack Tour and Conference in
June 2007:
http://www.extension.umn.edu/dairy/management/compostbarns.htm
Dr. Endres contact info: miendres@umn.edu
Two recent publications (contact wicks.14@osu.edu for a copy):
Barberg, A.E., M.I. Endres, J.A. Salfer, J.K.Reneau. 2006. Performance and Welfare of Dairy Cows in an Alternative Housing System in Minnesota. Journal of Dairy Science. 90:1575-1583.
Barberg, A.E., M.I. Endres, K.A. Janni. 2007. Compost Dairy Barns in Minnesota: A Descriptive Study. Applied Engineering in Agriculture. Vol.232(2): 231-238.
Discussion:
Dr. Keener (OSU), referring to reduction in somatic cell counts, asked if all the herds had previously been housed in tie-stall barns. Endres replied that all but one herd had previously been housed in tie-stall barns, with only one coming from a free-stall barn. That farm had both a free-stall and compost barn with separate bulk tanks for a period of time, allowing direct comparison of somatic cell counts for the systems. The compost barn had consistently lower counts.
Brian Gwin (Wayne Economic Development Council) asked about the design and orientation of the barns with respect to air flow. Endres reported that most were oriented east to west and some had 5-ft overhangs to minimize rain on the pack. While most had 14-16-ft sidewalls, some were only 12-ft high and ventilation was not as effective.
Harry Hoitink (OSU) suggested that the high temperatures recommended for most composting are not needed for this type of system as it may contribute to high ammonia levels. He suggested aerating more frequently and determining which management methods result in the healthiest cows, then evaluate what is happening biologically.
Mike Klingman (OSU) asked if there were issues with cows choosing different areas. Endres noted that the choice seems to be where not to lie down, particularly to avoid of cow pies.
Web link question: How much bedding is needed on a per cow per day basis? It is approximately 30 lbs/cow/day.
Mike Monnin (USDA-NRCS) asked if the density of cows would need to change for Ohio which has a warmer climate. Recommendations are currently 90-100 sq-ft/cow which is more than the 80-90 sq-ft/cow recommended for the compost barn. Endres responded that the effects of density in Minnesota were based on observation not research criteria, but did note that the summer of 2006, during the study, was unusually hot with temperatures in the 90’s (0F).
Keener asked if udder injury had been observed as that was a common problem in older bedded pack systems which recommended 70 sq-ft/cow. Endres noted that it was not a problem and suggested that it may have been the result of more space.
Gwin asked if the area per cow included the feed area. No, only the bedded pack area.
Hoitink asked if any of the manure from the feed alley is composted and how many farms are composting the pack that is removed. Endres was not aware of any composting the manure from the feed alley, but a couple are composting the pack and selling it to garden centers.
Hoitink noted that if the sawdust has been composted less than 100 days, it should not be spread on the fields as it will increase the risk of nitrogen immobilization, although the timing may vary with particle size. Endres noted that the first farm, built in 2001, has reported increased yields although they may be waiting before application.
Notes by Mary Wicks
The OCAMM (Ohio Composting and Manure Management) Program is funded by OARDC/OSU.