Growing Beef Newsletter
March 2026, Volume 16, Issue 9
Carcass disposal composting – a simple option for beef producers
Tony Mensing, ISU Extension and Outreach agricultural engineer
All phases of cattle production are faced with the challenge of mortality management. Despite the efforts of producers to provide good quality care for animals, some loss is inevitable as is the subsequent need to properly dispose of the carcass. Composting can be a relatively simple on farm disposal option.
The fine details for the biological process of composting may seem daunting, but if producers follow a few straightforward guidelines the natural composting processes will manage themselves. Basically, microbes want to do the work of composting, they just need to have enough resources available to make it possible. They need carbon, nitrogen, water, oxygen, and the right temperature range.
Composting microbes need about 30 parts of carbon for every 1 part nitrogen, moisture at about 50% by weight, at least 5% oxygen, and a thermophilic temperature. Getting into those particulars, it starts to sound like a pretty picky recipe, but the microbes want to do the work and will manage appropriately if we give them the chance. The carcass will provide nitrogen and moisture, our air is around 21% oxygen, and the microbial processes will produce heat, so the missing ingredient is a carbon source. It is important to set the microbes up for success because even though the process is fairly forgiving, extremes like too much moisture or oxygen deprivation can lead to a foul odor rotting mess instead of good carcass composting.
Carbon sources are sometimes called “browns” in the context of composting, and while there are many different options, a couple that might be readily available to cattle producers are corn stover and straw. Bedded pack manure may be another option if it is relatively high in bedding content, not overly moist. Wood chips might not be as common on cattle operations, but they are a great carbon source. Wood chips are especially good for the base of the compost pile and might be well worth the effort needed to procure them. Approximately 5 cubic yards or more of carbon material will be needed for every 1,000 pounds of carcass being composted. The carbon sources mentioned range from about 50 parts carbon to 1 part nitrogen to well over 100:1, so at the interface of the carbon source and the carcass, the nitrogen source, the microbes can manage themselves to their 30:1 ratio. Similarly, the interface between the high moisture carcass and dry carbon source will allow the microbes to work at appropriate moisture conditions, if the compost pile is built and maintained to shed precipitation so the carbon source doesn’t become too moist. The carbon source also needs to provide enough insulation for the microbial heat generated to be maintained while having enough pore space to allow fresh air to be drawn into the pile bringing additional oxygen for the processes.
Proper pile construction is the important piece that sets the microbes up for success and identifying a good site location is the first step. The site should not be in a flow path for runoff from precipitation events. It should be where there is enough physical room to work with heavy equipment needed for materials handling, and where it can stay for the 6 – 12 months that are needed to complete composting of a large carcass. A carbon source base layer large enough to maintain a 12” to 18” minimum buffer between the carcass and the edge of the base layer should be put down with a thickness of at least a couple of feet. This base layer carbon source needs to have enough structural integrity to maintain pore space for some air flow through the pile while supporting the weight of the carcass. It will also be tasked with absorbing excess moisture from the carcass during the initial carcass break down. These requirements are why wood chips serve this base layer function very well. After the base is built, the carcass should be placed on top of the base, laying on its side. The carcass doesn’t have to be pierced or dismantled for good composting but that would decrease the time needed to complete the process. The rest of the pile is built with additional carbon material so that the carcass is capped by at least 12” to 18” on the sides and the top with the pile being shaped so that it sheds precipitation. In the early days of the process there may be an initial let down of the carcass and settling of the carbon material that causes the pile to take on a concave top shape. If that’s the case, additional material should be added to maintain the pile’s ability to shed precipitation rather than collecting it.
With good pile construction using appropriate carbon source(s) and pile maintenance as needed, all the composting microbes’ needs should be met. Given enough time they should do their work with little to no additional intervention. The pile should be observed periodically to ensure that it doesn’t have a foul rotting flesh odor, isn’t leaching liquids, and hasn’t been affected by predators or varmints. All are signs something has gotten out of the appropriate working range and further investigation should be done to understand and correct the problem. A long-stemmed temperature probe, approximately 48” long, can also be used to observe what is happening inside the pile. Measuring the internal temperature of the pile and confirming it is in the 130 to 150 degrees Fahrenheit range can help confirm good composting is underway.
Producers will continue to need carcass disposal and while there are various options available, composting may be a good solution in many circumstances. Composting is a scientific biological process, but if producers provide microbes with the right resources they don’t have to get mired down in the gritty details because the microbes want to and will do the hard work themselves. Producers just have to build the compost pile appropriately for the microbes to be set up for success and then monitor the pile’s progress periodically throughout the process.
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