March 23, 2004
Ongoing research at Iowa State University is showing composting may be a viable way to dispose of large animal carcasses. A new Web site provides information on the research, preliminary results and guidelines for producers interested in composting animal carcasses.
The research began in 2002 at the request of the Iowa Department of Natural Resources (IDNR). "We were asked to study the feasibility and biosecurity of using on-farm composting for emergency disposal of beef or dairy animals in the event of a livestock disease outbreak or agro-terrorism in Iowa," said Tom Glanville, project coordinator and associate professor in ISU's agricultural and biosystems engineering department.
The Web site, http://www.abe.iastate.edu/cattlecomposting/, is organized to meet the anticipated needs of three different types of viewer. Those with only a casual interest in the project will find what they want on the executive summary page. For researchers, environmental officials, veterinarians and others who want more in-depth information, the page links listed under "Project in Detail" will give them what they want.
For producers and others who want to skip the science and just learn "how to do it," there is a link to the recently developed "Draft Guidelines for Emergency Cattle Mortality Composting."
During the first 16 months of the project, more that 40 tons of cattle carcasses have been composted. The Web site provides some preliminary results.
For instance, researchers have learned it generally takes eight to 12 months for the soft tissues and organs of a 1,000-pound carcass to decay under all three types of cover material being tested. Some trials begun during warm weather have taken less than six months.
Glanville said shorter times are feasible when compost piles are turned frequently. "We do not turn the piles in this research project because it is designed to simulate likely disposal procedures during a livestock disease emergency. In that case, turning could increase the risks of disease transmission," he said.
All three cover materials being field-tested - silage, ground cornstalks and a hay/manure mix - appear to achieve complete carcass decay in about the same amount of time.
The test units constructed with corn silage have the best potential for killing pathogens, since they typically produce the highest core temperatures in the shortest amount of time.
Odor in the immediate vicinity of the composting test units is low. In many cases, odor from the test units cannot be distinguished from the odors that are characteristic of the cover material.
Besides Glanville, others involved in the research project are Tom Richard and Jay Harmon, both associate professors of agricultural and biosystems engineering, and Don Reynolds, professor of veterinary microbiology and preventive medicine.
The research will continue through June 2005. Funding is provided through a continuing grant from IDNR with supplemental funds from the U.S. Department of Agriculture.
Editor's note: Photos of this research project are available on request.