Loss of livestock is a reality of raising farm animals. Mortality composting provides a sanitary, sustainable solution to disposal of carcasses. Turning mortalities or butcher residues into compost ensures that food energy removed from the farm in the form of feed is returned to the field or pasture. Some states may require permits for small or large-scale mortality composting sites, so check with the state department of agriculture for specific regulations and guidelines.
States have differing legislation on how far mortality compost sites should be located from wells, lakes and other bodies of water. Most are between 200 and 300 feet. The site should be elevated so that water does not collect in the compost pile and contaminate groundwater. The grade away from the site should be gradual to reduce runoff. Depending on state law, structures may need to be built around the compost piles to prevent scavengers and storms from wrecking the pile.
Livestock and poultry mortalities have a high ratio of nitrogen to carbon (N:C). To prevent the compost pile from going anaerobic (which is unsanitary and foul-smelling), carbon-rich content must surround the carcasses entirely. Sawdust, wood chips, litter, hay, husk and shavings are often used as carbon fillers. These are all by-products of other forms of production and agriculture, so using them in a compost pile prevents them from becoming problematic waste material.
If a proper balance of C:N is achieved, along with good aeration and moisture, the compost pile will reach temperatures exceeding 130 degrees F. At this temperature, pathogens in the carcass die. Absorbent carbon-filler bedding under the pile and rain cover above prevent runoff from carrying pathogens out of the pile. Structures built around the piles and several inches of carbon filler surrounding the carcass help deter disease-spreading scavengers and insects.
Compost piles undergo heat cycles that indicate high microbe activity. The microbe activity is what breaks down the carcass. When a heat cycle is complete, the pile is turned. This introduces more oxygen into the pile, and allows aerobic microbe activity to resume. Long-stem compost thermometers are used to monitor the interior temperature of the pile, helping farmers determine when to turn the pile. A mortality compost pile may need to go through two to three heat cycles before the carcasses are completely decomposed and the compost ready to be used.
Mortality composting provides a sanitary alternative of carcass disposal when rendering plants become too expensive or otherwise infeasible. The compost provided by mortality composting reduces the need to purchase and transport expensive fertilizers. When chemical fertilizers are no longer used, the beneficial microbe population in the soil can build, soil structure is improved, and fertilizer runoff no longer poisons water systems.