Composting Facility Design for Livestock Mortality Management

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-14

Key Takeaways

Composting livestock mortality is an aerobic biological process requiring a carbon source (e.g., wood shavings, sawdust, straw) and nitrogen source (carcass) to achieve an optimal carbon-to-nitrogen ratio of 25:1 to 40:1 for microbial decomposition.
Successful composting necessitates maintaining a moisture content of 50-60% (wrung-out sponge consistency) and ensuring adequate oxygenation through proper pile construction with a minimum of 12 inches of carbon cover material around carcasses.
Properly managed compost piles must reach and sustain internal temperatures of 130-150°F for several weeks to effectively inactivate common pathogens, with active composting typically lasting 3-6 months followed by a 3-6 month curing period.
Site selection is critical, requiring good drainage, a minimum of 100 feet from water sources and 300 feet from residences, year-round equipment accessibility, and compliance with local zoning and agricultural department regulations, including potential permit requirements.
Animals that have died from prion diseases, such as Chronic Wasting Disease (CWD) or Bovine Spongiform Encephalopathy (BSE), should not be composted as prions are not inactivated by this process; consultation with a veterinarian and regulatory agencies is mandatory for disease-specific restrictions.

Livestock mortality is an unavoidable part of farming. Every operation, whether a small hobby farm with a few cattle or a large commercial feedlot, must have a plan for dealing with dead animals. Rendering services are not available in every region, incineration is expensive, and burial is restricted in many areas due to groundwater concerns. Composting has emerged as a practical, biosecure, and environmentally sound method for managing livestock mortality on-farm. This guide covers the full planning process for a livestock mortality composting facility, from choosing a site and sizing your bins to managing the carbon source, monitoring the process, and using the end product. It is written for farm owners, managers, and operators who want to build a system that works within their existing operation and complies with local regulations.

At a Glance

Composting livestock mortality is a biological process that breaks down carcasses into a stable, soil-like material. It requires a carbon source, moisture, oxygen, and time.
The ideal carbon-to-nitrogen ratio for mortality composting is between 25:1 and 40:1. Wood shavings, sawdust, straw, and hay are common carbon sources.
Moisture content should be around 50 to 60 percent. The material should feel like a wrung-out sponge.
A minimum of 12 inches of carbon material is required beneath, between, and on top of carcasses. Larger animals need more cover material.
The active composting period lasts 3 to 6 months for most livestock, followed by a curing period of another 3 to 6 months.
Internal pile temperatures should reach 130 to 150 degrees Fahrenheit within the first week and stay elevated for several weeks to kill pathogens.
Site selection matters. Choose a location with good drainage, away from water sources, and accessible to equipment year-round.
Check with your state or provincial agricultural department and local zoning authority before building. Some regions require permits or have specific siting rules.
Never compost animals that died from certain neurological diseases, such as chronic wasting disease or bovine spongiform encephalopathy. Check with your veterinarian and local authorities for disease-specific restrictions.

Why Compost Livestock Mortality

Composting dead livestock is not a new idea, but it has gained widespread acceptance among farmers, researchers, and regulators over the past few decades. The process works because composting is a controlled biological decomposition. Microorganisms, primarily bacteria and fungi, break down organic matter. When you mix a high-nitrogen material like a carcass with a high-carbon material like wood shavings, the microbes multiply, generate heat, and convert the mixture into a stable product.

The benefits of mortality composting are substantial. It is cost-effective compared to rendering or incineration, especially for larger animals. It can be done on-farm with equipment most operations already own, such as a front-end loader or skid steer. The end product is a valuable soil amendment that can be applied to cropland or pasture. Composting also reduces the volume of the carcass significantly, often by 50 to 70 percent, and the remaining material is unrecognizable as animal tissue.

From a biosecurity standpoint, properly managed compost piles reach temperatures that kill many common pathogens, including bacteria and viruses that cause livestock disease. The high heat also discourages scavengers and flies when the pile is constructed correctly with adequate cover material. Composting keeps carcasses on-site, which means you are not transporting potentially infectious material across public roads or relying on a rendering service that may not be reliable.

There are also regulatory drivers. Many states and provinces have restricted or banned burial of livestock due to groundwater contamination risks. Rendering plants have closed in many rural areas, leaving farmers with few options. Composting is recognized by many agricultural agencies as an acceptable method of carcass disposal, and some states have published specific guidelines for it.

Understanding the Composting Process

Before you build a facility, you need to understand what happens inside the pile. Composting is an aerobic process, which means it requires oxygen. The microorganisms that break down the carcass consume oxygen and produce carbon dioxide, water, heat, and a stable organic material called humus. If the pile becomes anaerobic, meaning oxygen-depleted, the decomposition slows down and produces foul odors, including hydrogen sulfide and ammonia.

The composting process has two main phases. The first is the active phase, when temperatures rise and decomposition is rapid. This phase lasts 3 to 6 months for most livestock mortality. The second is the curing phase, when the pile cools and the remaining material stabilizes. Curing takes another 3 to 6 months. The total time from carcass placement to usable compost is typically 6 to 12 months, depending on the size of the animal, the time of year, and how well the pile is managed.

Temperature is the most important indicator of compost activity. A properly constructed pile will heat up within 3 to 7 days. Internal temperatures should reach 130 to 150 degrees Fahrenheit and stay there for several weeks. Temperatures above 160 degrees can kill the beneficial microbes and slow the process. Temperatures below 130 degrees suggest the pile is too wet, too dry, or lacking oxygen.

Moisture is the second critical factor. Microbes need water to survive, but too much water fills the pore spaces and excludes oxygen. The target moisture content is 50 to 60 percent. You can test this by taking a handful of material from the pile and squeezing it. If water drips out, the pile is too wet. If the material crumbles and does not hold its shape, it is too dry. If it feels like a wrung-out sponge, it is just right.

The carbon-to-nitrogen ratio, often written as C:N, is the third factor. Carbon provides energy for the microbes, and nitrogen provides protein for growth and reproduction. The ideal C:N ratio for composting is between 25:1 and 40:1. Livestock carcasses are high in nitrogen and have a C:N ratio of about 5:1 to 10:1. Wood shavings and sawdust are high in carbon, with a C:N ratio of 200:1 to 500:1. By mixing the two, you can achieve the target range. A general rule is to use 2 to 3 parts carbon material by volume for every 1 part carcass, but this varies with the density of the carbon source.

Regulatory Considerations and Permits

The first step in planning a livestock mortality composting facility is to check your local regulations. Rules vary significantly by state, province, and even county. Some regions have specific siting requirements, such as minimum distances from property lines, wells, streams, and roads. Others require a permit or registration. A few states have no specific rules for on-farm mortality composting, but that does not mean you can build anywhere. Local zoning ordinances and nuisance laws still apply.

Start by contacting your state department of agriculture or your provincial agricultural ministry. Many of these agencies have published guidelines for livestock mortality composting. Ask specifically about:

Permit or registration requirements
Minimum setbacks from water sources, property lines, and roads
Requirements for liners or impermeable bases
Restrictions on composting certain animals or diseases
End-product testing or land application rules

Your local soil and water conservation district or extension office can also be a good resource. They may have additional local knowledge and can help you design a system that works for your specific site conditions.

Do not skip this step. Building a facility that violates local regulations can result in fines, forced removal of the compost piles, and damage to your relationship with neighbors and regulators. It is much easier to adjust your plans before you build than to move an established composting site.

Site Selection

The location of your composting facility is one of the most important decisions you will make. A poorly sited facility can cause water pollution, odor complaints, and operational headaches. Take the time to evaluate your farm and choose the best available site.

Look for a location with the following characteristics:

Level or gently sloping ground. A slope of 1 to 3 percent is ideal for drainage without erosion.
Well-drained soil. Avoid areas that are prone to flooding or standing water. If your soil is heavy clay or poorly drained, you may need to build a base of gravel or crushed stone.
A minimum of 100 feet from any stream, pond, well, or other water source. Some states require more distance, so check your local regulations.
At least 300 feet from any neighboring residence, and consider prevailing winds when positioning the site. You want to avoid odor problems, even if the pile is managed well.
Accessible to a front-end loader, skid steer, or tractor with a loader, year-round. If your site is inaccessible during spring thaw or heavy rain, you will have problems.
Not visible from the road or your neighbor's property, if possible. This is not a legal requirement in most areas, but it can prevent complaints and reduce scavenger issues.
Away from areas where livestock congregate, such as barns, feedlots, and waterers. You want to minimize the chance of disease transmission and keep the area clean.

Consider the direction of prevailing winds. In most of North America, winds come from the west or southwest. Place the facility downwind of your home, barns, and livestock handling areas. If you have close neighbors, consider their location as well.

Think about future expansion. A facility that is adequate for 50 cows may not be adequate for 100 cows. Design your site with room to grow, or plan for a second location if your operation expands.

Facility Layout and Design

A well-designed mortality composting facility has several components. The exact layout depends on the size of your operation, the type of livestock you raise, and your equipment. But most facilities include the following elements:

A working pad or base
Compost bins or windrows
A carbon storage area
A water source and drainage control
A runoff collection system, if required

The Working Pad

The working pad is the surface on which you build your compost piles. It should be firm enough to support heavy equipment, even in wet weather. Options include:

Compacted gravel or crushed stone. This is the most common choice. A 6 to 8 inch layer of 1 to 2 inch crushed stone over a geotextile fabric works well. It provides good drainage and a stable surface.
Concrete. This is the most durable option but also the most expensive. A concrete pad is easy to clean and can be used for many years. It is a good choice for larger operations.
Compacted earth. This is the cheapest option but the least reliable. If your soil is well-drained and your climate is dry, a compacted earth pad may work. In wet climates, it will become muddy and difficult to work on.

The pad should be slightly larger than your bins or windrows. A 10 to 15 foot apron around each pile gives you room to maneuver equipment and to turn the piles if needed.

Compost Bins

Compost bins are enclosed structures that hold the carcass and carbon material. They can be built from a variety of materials, including:

Concrete blocks or poured concrete walls
Treated lumber or railroad ties
Corrugated metal panels
Hay bales or straw bales for temporary bins

The walls of the bins serve several purposes. They contain the compost material, help maintain the pile shape, and provide some insulation, which helps the pile heat up in cold weather. The walls also make it easier to build the pile in layers, which is important for proper composting.

Bin dimensions depend on the size of your livestock. For cattle mortality, a common bin size is 10 to 12 feet wide, 10 to 12 feet tall, and 20 to 30 feet long. This size can handle several mature cows at a time. For smaller animals like sheep, goats, or pigs, a bin of 8 to 10 feet wide, 6 to 8 feet tall, and 12 to 20 feet long is adequate.

The front of the bin should be open or have removable panels so you can load and unload with a bucket loader. Many farmers build three-sided bins, with the open side facing the equipment access area. Some build bins with a solid back wall and two side walls, leaving the front open.

The number of bins you need depends on your expected mortality rate and the time required for composting. A typical cattle operation experiences a mortality rate of 1 to 3 percent per year. If you have 100 cows, you might expect 1 to 3 deaths per year, but mortality can be higher in some years due to calving problems, disease outbreaks, or weather events. Most experts recommend having at least 2 to 3 bins so you can have one in the active phase, one in the curing phase, and one ready for new material.

If you are composting in windrows rather than bins, the same principles apply. A windrow is simply a long, narrow pile of compost material. Windrows are easier to build with a front-end loader and do not require walls. However, they require more carbon material per pound of carcass because there is more exposed surface area. Windrows are more common in large-scale operations.

Carbon Storage

You will need a large volume of carbon material to compost livestock mortality. A mature cow requires approximately 1,000 to 1,500 pounds of carbon material, or about 3 to 5 cubic yards. If you expect to compost 10 cows per year, you need 30 to 50 cubic yards of carbon material.

Plan for a dedicated storage area for your carbon source. This area should be:

Close to the compost bins to minimize hauling
Accessible to equipment
Covered or tarped to keep the material dry
Large enough to hold at least a year's supply

Wood shavings and sawdust are the most common carbon sources for mortality composting. They are absorbent, have a high carbon content, and are readily available in many areas. Straw and hay are also good options, but they break down faster and may need to be replenished during the composting process. Cornstalks, silage, and other crop residues can be used, but they may not be as absorbent.

Avoid using materials that are contaminated with pesticides, herbicides, or other chemicals. These can kill the compost microbes and may leave residues in the finished compost.

Water and Drainage

Composting requires moisture, and you will likely need to add water during dry periods. A nearby water source, such as a hydrant or a water tank, is important. You can use a hose to add water to the pile, or you can use a water wagon or sprayer.

Drainage is equally important. You do not want runoff from the compost piles to enter streams, ponds, or groundwater. The compost pad should be sloped so that runoff is directed to a collection area. In many states, you are required to collect and contain runoff from compost facilities.

A simple runoff collection system consists of a berm or swale around the compost pad that directs water to a holding pond or tank. The collected runoff can be applied to cropland or pasture as a liquid fertilizer. This is not just a regulatory requirement. It also prevents the accumulation of nutrients in one area and protects water quality.

Sizing Your Facility

The size of your composting facility depends on several factors:

The number and size of animals on your farm
The expected mortality rate
The type of livestock you raise
The time required for composting in your climate
The amount of carbon material you can source

A general approach is to estimate your annual mortality and multiply by the volume of compost that will be produced. A mature cow produces about 2 to 3 cubic yards of compost. A calf produces about 1 cubic yard. A sheep or goat produces about 0.5 cubic yards. A pig produces about 0.5 to 1 cubic yard, depending on size.

For example, a farm with 100 beef cows might expect 2 to 3 deaths per year. If each cow requires 3 to 5 cubic yards of carbon material and produces 2 to 3 cubic yards of compost, you need about 10 to 15 cubic yards of bin space per cow. With 3 cows per year, you need 30 to 45 cubic yards of active bin space. Add another 30 to 45 cubic yards for curing space, and you have a total of 60 to 90 cubic yards.

A bin that is 10 feet wide, 10 feet tall, and 20 feet long holds about 2,000 cubic feet, or about 74 cubic yards. Two such bins would provide 148 cubic yards of total capacity, which is more than enough for this example.

If you are raising animals in confinement, your mortality rate may be higher. For example, a swine operation might experience 2 to 5 percent mortality per year. A poultry operation can have higher mortality rates, but the smaller carcass size makes composting easier.

The key is to build more capacity than you think you need. It is better to have an empty bin than to be caught without a place to put a carcass. Consider the worst-case scenario, such as a disease outbreak or a severe weather event, and plan for that.

Carbon Source Selection and Management

The carbon source is the most important input in mortality composting. It provides the energy for the microbes, absorbs moisture from the carcass, and creates the pore spaces that allow oxygen to flow through the pile. Choosing the right carbon source and managing it properly is essential for success.

Wood Shavings and Sawdust

Wood shavings are the gold standard for mortality composting. They are absorbent, have a high carbon content, and break down slowly enough to maintain their structure throughout the composting process. Sawdust is also good, but it is finer and can pack down more easily, which may restrict airflow.

When selecting wood shavings, look for clean, dry material. Avoid shavings that are contaminated with manure, dirt, or other debris. The particle size should be consistent, with most pieces between 0.5 and 2 inches. Fine shavings and dust can be used, but they should be mixed with coarser material to maintain porosity.

The moisture content of the shavings matters. Dry shavings will absorb moisture from the carcass, which is good. Wet shavings can make the pile too wet and may not absorb enough moisture. Store shavings under cover or tarp them to keep them dry.

Straw and Hay

Straw and hay are acceptable carbon sources, but they have some limitations. They break down faster than wood products, which means the pile may settle more and require additional cover material during the composting process. Straw also has a lower carbon content than wood and may need to be used in larger quantities.

If you use straw, choose a coarse, long-stemmed variety. Barley straw and wheat straw are good options. Avoid moldy or spoiled straw, which may introduce unwanted organisms to the pile.

Hay can be used, but it is often more expensive than straw and may contain weed seeds. If you use hay, be aware that it will decompose quickly and may need to be replenished.

Crop Residues

Cornstalks, corn cobs, and other crop residues can be used as carbon sources. These materials are often available on the farm at little or no cost. However, they may not be as absorbent as wood shavings, and they can be difficult to handle if they are not chopped or shredded.

If you use crop residues, chop them to a consistent size to improve mixing and airflow. You may need to add more material during the composting process as the residues break down.

Other Materials

Some farmers use shredded paper, cardboard, or other recycled materials as carbon sources. These can work, but they may contain inks or coatings that are not desirable in the finished compost. They also break down quickly and may not provide adequate structure.

Manure or compost from other sources can be used as a carbon source, but this is not recommended for mortality composting. Manure is high in nitrogen and may upset the carbon-to-nitrogen ratio. It can also introduce pathogens to the pile.

Storage and Handling

Store your carbon source in a dry, accessible location. A three-sided bin or a covered shed works well. The material should be protected from rain and snow, as wet carbon material is harder to work with and may not absorb enough moisture from the carcass.

You will need to handle the carbon material multiple times during the composting process. Use a front-end loader or skid steer to move it from storage to the compost bins. Some farmers use a manure spreader or a compost turner to mix the material.

Building the Compost Pile

Proper pile construction is the most critical step in mortality composting. A well-built pile will heat up quickly and decompose the carcass efficiently. A poorly built pile will be slow, smelly, and may not reach temperatures high enough to kill pathogens.

The basic procedure for building a mortality compost pile is as follows:

Place a base layer of carbon material on the floor of the bin. The base layer should be at least 12 inches thick, and 18 to 24 inches is better for large animals. This layer absorbs fluids from the carcass and provides insulation from the ground.

Place the carcass on the base layer. Position the carcass in the center of the bin, leaving at least 12 inches of space between the carcass and the bin walls. If you are composting multiple carcasses, space them at least 12 inches apart.

Cover the carcass with a layer of carbon material. The cover layer should be at least 12 inches thick, and 18 to 24 inches is better. Make sure the carcass is completely covered. Any exposed flesh will attract flies and scavengers.

If you are composting multiple carcasses in one bin, repeat steps 2 and 3 for each carcass. Each carcass should have its own carbon cover.

Add a final layer of carbon material over the entire pile. This layer should be at least 6 to 12 inches thick. The top of the pile should be slightly peaked or domed so that rain runs off rather than soaking in.

If the carbon material is dry, add water to the pile. The goal is to achieve a moisture content of 50 to 60 percent throughout the pile. You may need to wet the carbon material as you build the pile, especially if you are using dry wood shavings.

Label the pile with the date and the number of carcasses. This will help you track the composting process and know when the pile is ready to be turned or used.

For large animals, some experts recommend opening the body cavity before placing the carcass in the pile. This allows the microorganisms to access the internal organs more quickly and speeds up decomposition. However, this is not always practical or safe. If you do open the body cavity, use appropriate personal protective equipment and be aware of the risk of disease transmission.

The size of the pile matters. A pile that is too small will not heat up properly. A pile that is too large may not get enough oxygen in the center. For cattle mortality, a pile that is at least 6 feet tall and 10 feet wide will generate enough heat. For smaller animals, a pile of 4 to 5 feet tall and 6 to 8 feet wide is adequate.

Managing the Composting Process

Once the pile is built, the composting process begins. Your job is to monitor the pile and make adjustments as needed. The key management tasks are:

Monitoring temperature
Monitoring moisture
Turning the pile, if necessary
Adding carbon material, if needed
Controlling flies and odors

Temperature Monitoring

Temperature is the best indicator of compost activity. You should check the internal temperature of the pile within 3 to 5 days of building it. Use a long-stemmed compost thermometer, which is available from farm supply stores and online retailers. Insert the thermometer into the pile at a depth of 18 to 24 inches, in several locations.

The temperature should rise to 130 to 150 degrees Fahrenheit within the first week. If the temperature does not rise, the pile may be too dry, too wet, or lacking the right carbon-to-nitrogen ratio. If the temperature exceeds 160 degrees, the pile may be too hot, and you should consider turning it or adding more carbon material to cool it down.

Monitor the temperature weekly for the first month, then every 2 to 4 weeks for the remainder of the active composting period. Keep a record of the temperatures so you can track the progress of each pile.

Moisture Management

Check the moisture content of the pile at the same time you check the temperature. Use the squeeze test described earlier. If the pile is too dry, add water. If it is too wet, add dry carbon material and turn the pile to mix it in.

In most climates, you will need to add water during the summer months. In wet climates, you may need to cover the pile to prevent it from becoming waterlogged. A tarp or a roof over the bins can help control moisture.

Turning the Pile

Mortality composting does not require frequent turning. In fact, turning the pile too often can slow the process by releasing heat and disrupting the microbial community. Most experts recommend leaving the pile undisturbed for the first 60 to 90 days. After this initial period, you may turn the pile once or twice to mix the remaining carcass material with the carbon source and to add oxygen.

Turning is easier with a front-end loader or a skid steer. You can also use a dedicated compost turner if you have one. When turning, be careful not to expose any remaining carcass material. If you see bones or other recognizable tissue, cover them with carbon material and return the pile to its original shape.

After turning, the pile should heat up again within a few days. This secondary heating is normal and indicates that the microbes are active. If the pile does not reheat, the composting process is nearly complete.

Odor and Fly Control

A properly managed mortality compost pile should not produce significant odors. If you detect a foul smell, the pile is likely too wet, too dry, or lacking oxygen. The most common cause of odor is anaerobic conditions, which occur when the pile is too wet or too compacted.

To control odors:

Add more carbon material to absorb moisture and improve airflow
Turn the pile to introduce oxygen
Reduce the amount of water you are adding
Make sure the carcass is completely covered with carbon material

Fly control is also important. Flies are attracted to exposed flesh and moist organic material. The best way to control flies is to make sure the carcass is fully covered with at least 12 inches of carbon material. If flies are still a problem, you can use a fly trap or an approved insecticide around the compost area.

Cold Weather Composting

Composting livestock mortality in cold weather is possible, but it requires some adjustments. The microbial activity that drives composting slows down at low temperatures, and the pile may not heat up as quickly or as high. In regions with harsh winters, you may need to plan for this.

The most important factor in cold weather composting is pile size. A larger pile retains heat better than a small pile. Aim for a pile that is at least 8 to 10 feet tall and 12 feet wide for cattle mortality. The insulation provided by the carbon material is also important. A thicker cover layer, 18 to 24 inches, will help retain heat.

You may also need to use a different carbon source in the winter. Wood shavings and sawdust are better insulators than straw or hay. If you are using a mix of materials, increase the proportion of wood products.

Another strategy is to build the pile in late fall, before the ground freezes. The pile will generate heat initially, and this heat will be retained by the insulating carbon layer. If you can get the pile through the first few weeks, the composting process will continue slowly through the winter and speed up again in the spring.

Some farmers maintain a supply of composted material or aged manure to use as a "starter" for winter piles. This material contains active microbes and can help the pile heat up faster. Mix a few shovel-fulls of compost into the carbon material as you build the pile.

Do not add water to a winter pile unless it is absolutely necessary. Water can freeze and create ice layers that restrict airflow. If the pile is too dry, it will still compost, just more slowly.

Common Mistakes and How to Avoid Them

Even experienced farmers make mistakes when they first start composting livestock mortality. Here are the most common problems and how to avoid them.

Using Too Little Carbon Material

The most common mistake is not using enough carbon material. Farmers often try to save money by using less shavings or straw, but this leads to problems. Without adequate carbon, the pile will be too wet, too smelly, and will not heat up properly. It may also attract flies and scavengers.

Follow the rule of at least 12 inches of carbon material beneath, between, and on top of each carcass. For large animals, use 18 to 24 inches. It is better to use too much carbon than too little.

Building the Pile Too Small

A small pile will not generate enough heat to compost effectively. If you are composting a single calf or a few sheep, the pile may be too small to reach the target temperature. This is especially true in cold weather.

To solve this problem, combine multiple carcasses in one bin, or build a larger pile with extra carbon material. You can also use a smaller bin for small animals, which will concentrate the heat.

Not Monitoring the Pile

Composting is not a set-and-forget process. You need to monitor the pile regularly, especially in the first few weeks. If you do not check the temperature and moisture, you may not catch problems until they are serious.

Set a schedule for monitoring and stick to it. Check the temperature and moisture weekly for the first month, then every 2 to 4 weeks after that. Keep records of your observations.

Turning the Pile Too Early

Turning the pile too early releases heat and disrupts the composting process. The pile needs time to reach peak temperatures and maintain them for several weeks to kill pathogens. Wait at least 60 to 90 days before turning a mortality compost pile.

Using the Compost Too Soon

Mortality compost is not ready to use until it has gone through both the active and curing phases. Using the compost before it is fully cured can introduce pathogens to your fields and may harm plants. The finished compost should be dark, crumbly, and have an earthy smell. It should not contain any recognizable carcass material.

Composting the Wrong Animals

Not all animals should be composted. Some diseases, such as chronic wasting disease in deer and elk and bovine spongiform encephalopathy in cattle, are caused by prions that are not destroyed by composting. If you suspect an animal died from a prion disease, do not compost it. Check with your veterinarian and follow the recommendations of your state or provincial agricultural agency.

Monitoring and Recordkeeping

Good recordkeeping is essential for a successful mortality composting program. Records help you track the progress of each pile, identify problems early, and demonstrate compliance with regulations. They also help you plan for future capacity needs.

For each compost pile, record:

The date the pile was built
The number and type of animals composted
The approximate weight of the carcasses
The type and amount of carbon material used
The date and results of each temperature check
The date and results of each moisture check
Any adjustments made, such as adding water or carbon material
The date the pile was turned
The date the pile was considered finished

You can use a simple notebook, a spreadsheet, or a dedicated recordkeeping app. The important thing is to be consistent and accurate.

Temperature records are particularly important because they demonstrate that the pile reached temperatures sufficient to kill pathogens. Most state guidelines require temperatures of at least 130 to 140 degrees Fahrenheit for a specified period, often 3 to 5 days. Your records should show that you met these requirements.

If you are composting under a permit or registration, your regulatory agency may require you to submit records. Even if not required, keeping records is a good business practice.

End Product Use and Testing

The end product of mortality composting is a stable, soil-like material that can be used as a soil amendment. It is not the same as fresh manure, and it should be handled and applied differently.

The finished compost should be dark brown to black, crumbly, and have an earthy smell. It should not contain any recognizable carcass material, although some small bone fragments may remain. These fragments are brittle and will break down over time, but you may want to screen them out if you are applying the compost to a fine-textured soil.

Mortality compost is typically higher in nutrients than compost made from manure alone. A typical analysis might show:

Nitrogen: 1 to 2 percent
Phosphorus: 1 to 2 percent
Potassium: 1 to 2 percent
Calcium: 2 to 4 percent

The exact nutrient content depends on the carbon source, the type of animal, and the composting process. If you are applying the compost to cropland, consider having it tested by a soil testing laboratory. This will help you determine the appropriate application rate.

Mortality compost can be applied to:

Cropland, including fields used for grain, forage, or vegetables
Pasture and rangeland
Home gardens and landscaping (if the compost is fully cured)

Do not apply mortality compost to land that is frozen, snow-covered, or saturated. This can cause runoff and water pollution. Follow the same application guidelines as for other organic amendments, such as manure or compost.

If you are unsure about the quality of your compost, you can have it tested for pathogens. Most soil testing laboratories offer compost testing, including tests for E. coli, Salmonella, and other pathogens. This is especially important if you plan to use the compost on food crops or in a home garden.

When to Call a Veterinarian or Extension Agent

Composting is a management practice, not a veterinary procedure. However, there are times when you should seek professional advice.

Call your veterinarian if:

You are unsure about the cause of death of an animal
You suspect a reportable or zoonotic disease
You are seeing an unusual number of deaths on your farm
You have questions about disease-specific disposal requirements

Your veterinarian can help you determine whether composting is appropriate for a particular animal and can advise you on biosecurity measures.

Call your local extension agent or agricultural advisor if:

You are designing a new composting facility
You have questions about siting, permits, or regulations
You are having problems with your compost pile, such as odors or slow decomposition
You want to have your compost tested
You are considering changes to your mortality management plan

Extension agents have access to research-based information and can help you troubleshoot problems. They can also connect you with other farmers who have experience with mortality composting.

Scaling Up for Large Operations

The principles of mortality composting are the same regardless of the size of your operation, but the scale changes the approach. A large feedlot, dairy, or swine operation may need a much larger facility and more sophisticated management.

For large operations, consider the following:

Dedicated staff. Someone needs to be responsible for the composting facility. This person should be trained in proper pile construction, monitoring, and recordkeeping.
Larger equipment. A front-end loader with a larger bucket or a dedicated compost turner may be needed to handle the volume of material.
Multiple bins or windrows. Large operations often use windrows rather than bins because they are easier to build and manage with large equipment.
More carbon storage. You will need a significant amount of carbon material, and you should have a reliable supply chain.
More rigorous monitoring. Large operations should monitor temperature and moisture more frequently and keep detailed records.
Nutrient management planning. The finished compost from a large operation can be a significant source of nutrients, and you should have a plan for applying it to cropland.

If you are managing a large operation, consider working with an agricultural engineer or a consulting agronomist to design your facility. The investment in professional design can pay for itself in improved efficiency and regulatory compliance.

Economic Considerations

Mortality composting can save money compared to other disposal methods, but it is not free. The main costs are:

Construction of the facility, including the pad, bins, and drainage
Carbon material, which may be purchased or produced on-farm
Labor for building, monitoring, and turning the piles
Equipment costs, including fuel and maintenance

The main savings are:

Avoided costs of rendering, incineration, or burial
Value of the finished compost as a soil amendment
Reduced risk of regulatory fines or cleanup costs

For most farms, the cost of building a mortality composting facility is recovered within a few years. The exact payback period depends on the number of animals you compost and the cost of alternative disposal methods.

If you are considering mortality composting, start with a simple system and expand as you gain experience. You can always add bins or improve your facility later.

Frequently Asked Questions

How long does it take to compost a cow?

A mature cow takes 6 to 12 months to fully compost, depending on the time of year and how well the pile is managed. The active phase lasts 3 to 6 months, during which the carcass breaks down and the pile reaches high temperatures. The curing phase lasts another 3 to 6 months, during which the material stabilizes. In cold climates, the process may take longer.

Can I compost animals that died from disease?

Yes, for most diseases. The high temperatures achieved during composting, 130 to 150 degrees Fahrenheit for several weeks, kill most pathogens that affect livestock. However, some diseases are caused by prions, which are not destroyed by composting. These include chronic wasting disease in deer and elk and bovine spongiform encephalopathy in cattle. Check with your veterinarian before composting an animal that died from a suspected prion disease.

What is the best carbon source for mortality composting?

Wood shavings are generally the best carbon source because they are absorbent, have a high carbon content, and break down slowly. Sawdust is also good but is finer and may pack down. Straw and hay can be used but break down faster. The most important thing is to use a material that is dry, clean, and high in carbon.

Do I need to turn the compost pile?

No, you do not need to turn a mortality compost pile frequently. In fact, turning too often can slow the process. Most experts recommend leaving the pile undisturbed for the first 60 to 90 days. After that, you may turn the pile once or twice to mix the remaining material and add oxygen.

How do I know when the compost is finished?

Finished compost is dark brown to black, crumbly, and has an earthy smell. It should not contain any recognizable carcass material, although small bone fragments may remain. The pile will have cooled to near ambient temperature, and it will not reheat when turned. If you are unsure, you can have the compost tested by a soil testing laboratory.

Can I compost in the winter?

Yes, but the process will be slower. To compost in cold weather, build a larger pile, use more carbon material, and make sure the pile is well-insulated. The pile should be at least 8 to 10 feet tall and 12 feet wide for cattle mortality. The composting process will slow down but will resume as the weather warms.

What do I do with the finished compost?

The finished compost can be applied to cropland, pasture, or gardens as a soil amendment. It contains valuable nutrients, including nitrogen, phosphorus, and potassium. Have the compost tested before applying it to determine the appropriate application rate. Do not apply compost to frozen or saturated ground.

Do I need a permit to compost livestock mortality?

Regulations vary by state and province. Some regions require permits or registration for mortality composting facilities, while others do not. Contact your state department of agriculture or provincial agricultural ministry to learn about the requirements in your area. You should also check with your local zoning authority.

Related Farming Guides

This section will be populated with links to related farming guides on livestock management, biosecurity, and soil health. Check back for updates.

Related Clinical & Scientific Guides

References

USDA Farm Management: https://www.farmers.gov/
FAO Farm Management: https://www.fao.org/farmer-field-schools/en/
FAO Animal Production and Health: https://www.fao.org/animal-production/en/
WOAH (World Organisation for Animal Health): https://www.woah.org/en/home/

This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.