Mortality Composting

Mortalities are an unfortunate reality for livestock operations. Whether they’re caused by disease or natural disaster, losses of livestock do occur and these mortalities must be managed responsibly. The state of Nebraska allows for disposal of dead animals via several methods including burial, rendering, incineration, composting, and landfilling. Incineration (burning) is often not economical and burial can present a risk of groundwater contamination in some regions depending on soil type and depth to groundwater. When a loss occurs due to disease, there is additional concern that burial will not provide a way for the disease-causing organism to be rendered inactive, presenting a risk of disease reoccurrence. While rendering has likely been the most commonly used disposal method, rendering facilities in some regions are becoming less accessible. Additionally, losses of livestock due to diseases like porcine epidemic diarrhea virus (PEDV) and highly pathogenic avian influenza (HPAI) are often not collected by renderers due to concerns of disease transfer. Composting is an effective means of mortality disposal that can be done on any size livestock operation with any size animal and most farms are already equipped with the necessary materials and implements.

In years past, some people felt that large animals could not be composted and the state of Nebraska limited composting of mortalities to animals weighing less than 600 pounds. Research at a number of universities has shown that animals of any size can be composted – with one east coast university even composting a beached whale! A demonstration site at Curtis, Nebraska organized by USDA-NRCS and UNL was highly successful in composting a number of animals including mature cattle, calves, and horses. At the conclusion of that demonstration, animals had been broken down into an organic-rich soil amendment with little to no odor and a minimal amount of brittle bones remaining.

The thought of dead animals probably invokes fears of horrible smells. The good news is that if composting is done properly, it is, for the most part, odorless. When fully composted, the end product smells “earthy” as any true compost will. In fact, the Curtis location was moved from a pasture several hundred yards from the campus to a location very close to the dormitories once the lack of offensive odor was exhibited. The key to composting mortalities is to provide the necessary carbon, nitrogen, and moisture to enable decomposition of the pile materials by microorganisms, and to cover the piles well with dry carbon material thus insulating the pile, preventing heat loss, minimizing odor, and discouraging scavenging animals from disrupting the pile.

Another advantage of composting is the inactivation of diseases. Because properly built and managed piles reach high temperatures, pathogenic bacteria and viruses are killed during the process. With recent outbreaks of highly pathogenic diseases like PEDV and HPAI, composting mortalities allows producers to dispose of mortalities in a manner that decreases the risk of transmission to other livestock operations because composting can be done on-farm.

Preventing water contamination and decreasing risks should be of utmost importance when managing manure and mortalities no matter the size of your livestock operation.