Carcass Disposal Options
Each state has separate regulations regarding the disposal of animal carcasses. To view the regulations from your state, select it from the drop down box and the click View PDF button and a new window will open with the PDF file of that state.
Carcass Disposal Information
Data was kindly provided by Dr. Michael Byers
Despite the best care afforded them, farm animals will succumb to injury, disease, and other factors, and the management of mortalities will always be an important aspect of livestock farming. Typical methods for the disposal of animal mortalities have included rendering, burial, incineration, and composting. Decreased availability of rendering services and biosecurity issues have made this disposal option less appealing, while incineration can be costly and can adversely affect air quality. Burial can be difficult, especially during the winter months, and has the potential to contaminate groundwater. For these reasons, composting is often the method of choice for mortality disposal.
- Water Table
- Local Approval
- Fuel Sources
- Air Curtain Incinerator:
- Self Contained
- More Information at Airburners.com
- Composting can be defined as the controlled decomposition of organic materials. Decomposition occurs when organic materials go through a "slow cooking" process as microorganisms metabolize the organics. Rapid decomposition is an aerobic process, requiring oxygen. The process will produce carbon dioxide, water vapor, heat, and compost. The combination of the cooking process, rapid degradation, and compost cover minimizes odor and flies. In order to generate a healthy poultry composting process, the following four elements are necessary:
Proper nutrient mix: The carbon:nitrogen ratio (C:N) is very important for microorganisms to process the organic materials into compost. The C:N should be in the range of 20:1 to 35:1. A carbon:phosphorus ratio (C:P) of 100:1 to 150:1 is also desirable.
Moisture: Moisture is also very important for the microbial activity to process the organic material into compost. A range of 40 to 60 percent is desirable. The process will not operate effectively if the material is too dry or too wet.
Temperature: If the C:N ratio, moisture, and oxygen are at the proper levels, thermophilic aerobic bacteria activity will cause the mass to heat to temperatures ranging from 135° to 145°F. Carbon dioxide and water vapor are generated as byproducts of the composting process. Temperature should be monitored by using a 36-inch stem composting thermometer.
pH Control: A proper C:N ratio should keep pH in check. However, if for some reason the pH level approaches 8, ammonia and other odors may become a problem. The pH needs to be reduced by adding such products as granular ferrous sulfate. A pH in the range of 6.5 to 7.2 is best for composting.
The materials needed for composting are water; a bulking material such as straw, wood chips, or sawdust; dead birds; and poultry litter. Sawdust works well by itself as the only bulking material. These materials are layered into a pile or windrow no more than 12 feet wide and 7 feet high. The length of the windrow can be as long as necessary to hold the number of birds to be composted. Provide at least 1 cubic foot of bulking material per 10 pounds of expected mortality (for example: 1,000 birds at 3 pounds each would require 300 cubic feet [11 cubic yards] of bulking material).
- Carbon Source Requirements
- Large animals such as cows and horses should be composted in sawdust, moist but not wet silage, screenings from a manure flush system or other carbon material with discrete small particles. A base layer of dry material should be placed at least one foot deep under the animal to act as a sponge for fluids that seep from the carcass. The bigger the animal the deeper the base layer. The base layer should extend at least two feet beyond all sides of the animal. The animal should be covered with compost ingredient material to form a peaked pile such that a minimum of one foot of cover exists all around the animal. Multiple large animals can form a windrow.
As to the exact quantity per animal it depends on the size but for mature cows and horses it might range from 4 to 6 cubic yards of material per animal.
- Carbon Medium
- Sawdust is the best medium to mix with mortalities. Other high carbon materials including chopped straw, corn cobs, corn silage, mixture of manure and straw/sawdust, etc. may be possible but sawdust in research trials at the Ridgetown College of Agricultural Technology gave highest temperatures and fastest breakdown of materials.
For every kilogram of mortality to be composted one kilogram of sawdust is needed. If the mixture gets too dark during the compost period, more sawdust should be added. The mortalities can be buried into the medium as they occur. (A 20 litre pail of sawdust weighs approximately five kilograms.)
- Animal Preparation
- Usually large animals are cut to expose internal organs to the sawdust or other compost materials you use. Large muscle masses can be sliced to increase surface area. Leg tendons need to be sliced so that the animal can be laid backbone down and legs folded. However, some farmers make no preparation and simply bury the animal in compost material with no less success at carcass degradation.
- Site Preparation
- The composting site begins with a twelve inch layer of sawdust. This layer will insulate the composting material from the outside environment, provide carbon to fuel the composting process, and provide sufficient space between particles to allow gas flow and preserve the aerobic nature of the pile. Alternative carbon sources such as poultry litter or bedding material can be substituted for sawdust with similar results. Ensuring adequate moisture content within the compost pile is necessary for optimal activity, and using a carbon source already possessing significant water content will reduce the requirement for additional water.
Carcasses are then evenly placed on this carbon layer, taking care to keep them at least six inches from the side walls. These carcasses are then covered with another twelve inches of sawdust, and water is added to this layer to keep the pile uniformly moist. Liquid manure can be substituted for water. As more mortalities become available, additional layers are added to the pile in the same manner. If a large animal is added to the pile, it may be necessary to dig a trough in the existing pile into which the animal can be inserted and then covered.
- A: Static Piles
- Static piles take a long time to compost.
- B: Open Windrows
- Open windrows are labor intensive
A windrow 12 feet wide by 6 feet long will hold approximately 300 pounds of mortality per foot of length. The materials required per foot of windrow length (300 pounds of mortality) would be 14 cubic feet of litter (400 pounds) and 16 cubic feet of wood chips, sawdust, or straw (700 pounds).
- C: In-Vessel Composting
- Construction costs are often prohibitive
- D: AG-Bag Environmental's EcoPOD Technology
- Site Requirements
- Grading- hard packed surface
- Water- for adding moisture before filling pod
- Electricity for powering the aeration system