By KEVIN WALKER
EAST LANSING, Mich. — The Michigan Ag Expo will feature a demonstration on composting animal remains as an alternative to burial, as it has in past years.
“This year’s Ag Expo is going to be focused on what to do with the bones that are remaining,” said Tom Guthrie, Michigan State University equine extension educator.
Once the bones are all that remain of a dead animal, those too must be disposed of. Partially decomposed bones can be applied to a field, buried or broken down further by chemicals. “This year’s demonstration just takes it to the next step,” Guthrie said.
He stated all farm operators know taking care of livestock mortality on a farm is just a reality. Composting is an alternative for farmers to use. It can be “more efficient than burial. Burial might not be as efficient as composting.”
A dead horse can be decomposed in 30-60 days if it’s done properly. Guthrie stated a dead animal can be completely decomposed except for the bones in as little as 30 days, with the right mixture of bulking agents.
These include sawdust, chopped straw, woodchips, leaves, spelt hulls, bean pods, grass clippings, shredded cardboard or newspaper, chopped cornstalks, fresh manure and other materials listed in the MSU bulletin E3168 Composting Dead Horses.
The right mixture of these agents will ensure enough air can get into the compost pile, but not too much air. “Bulking agent particle size is important because it affects the air spaces within the pile,” the bulletin states. “If particle size is too fine, oxygen cannot move through the pile. Limited microbial activity and odor production result.
“Fine particles, however, are absorbent and help capture fluids released from tissues during composting. If particle size is too large and variable, there is too little interface between tissues and the carbon source. This limits microbial metabolism. Excessive coarseness allows too much air through the pile, which cools the pile.
“A non-uniform particle size range of 0.1-2 inches is recommended. Particles in this size range provide porosity, optimal surface area and absorption of odors and liquids. The compost pile should be a maximum of 5-6 feet tall to prevent compaction and the loss of air in the pile,” it notes.
The bulletin provides the correct carbon-to-nitrogen ratio for a good compost pile, proper moisture content range, temperature range, oxygen concentration and pH. It also discusses other rules for making a compost pile to degrade animal tissue, including the floor of the pile, its placement relative to neighbors, water sources and similar matters.
The demonstration at this year’s Ag Expo will show an animal that’s already been decomposed in a compost pile, to demonstrate the effectiveness of the composting technique.
It will be conducted all three days at 11 a.m., off-site at the swine farm, by MSU animal sciences professor Dale Rozeboom.
Bulletin E3168 is available free of charge. Other materials on dead animal disposal in Michigan can be found online at www.msu.edu/~rozeboom/ catrn.html