Animal Carcass Disposal: Know Your Options

While carcass disposal is not a pleasant topic, it is a subject of significant economic and environmental concern. What are the options for carcass disposal?

In many instances the cause of death needs to be determined, so the body is transported to a diagnostic laboratory for a necropsy examination. Alternatively, the animal may be necropsied on the farm by a veterinarian and samples shipped to the laboratory. Other times, the animal may simply need disposal.

Most states have statutes and regulations governing animal disposal. Some areas have rendering or hauling services that will come to the farm to remove the animal. Carcasses picked up for rendering are usually processed to yield a product and may be converted into fertilizer or even biofuels.

In Kentucky, burial on the farm is permitted. By regulation, the burial must be within 48 hours after the carcass is found. The site of burial must never be covered with the overflow of ponds or streams and must not be within 100 feet of any waterway, sinkhole, well, spring, public highway, residence, or stable. The body must be placed at least four feet deep in the earth, with the thoracic and abdominal cavities incised. The body is then covered with at least two inches of lime and three feet of dirt. In addition to burial on the farm, animal remains may also be disposed of in approved landfills and composting facilities.

The remains of animals taken to a diagnostic laboratory also have to have proper disposal. Several options are used by laboratories. Rendering is one of the main ways of disposal, since it can accommodate a large volume of material and is economical. However, recently rendering has become more regulated and restricted, primarily due to concerns over bovine spongiform encephalopathy (BSE). While currently a good method of disposal, rendering as a viable, long-term means is uncertain.

A primary alternative to rendering is incineration or cremation. This method is expensive but ensures that infective or potentially dangerous material is destroyed. Individual animals can be cremated and the ashes returned to the owner for burial, or incineration can be employed with multiple carcasses simultaneously.

A new methodology is tissue digestion by alkaline hydrolysis. Alkaline hydrolysis is a simple, natural process by which the body's complex molecules are broken down to simple components by exposure to a strong base (high pH) under elevated temperature and pressure. This process occurs in nature when animals are buried in alkaline or neutral pH soil. With this method, the carcass is converted to a sterile soluble solution in a tissue digester and a residue consisting of the inorganic component (ash) of the bones. Tissue digesters can be rather large, up to a capacity of 10,000 pounds, allowing for disposal of large amounts of animal tissue. An added benefit is that infective prions associated with BSE, scrapie in sheep, or chronic wasting disease in deer are inactivated by alkaline hydrolysis. This technology will likely become more widely used in the future.

CONTACT: Dr. Neil Williams; 859/253-0571; Livestock Disease Diagnostic Center; University of Kentucky; Lexington, Ky.

Read more about carcass disposal.  

This is an excerpt from the January 2009 issue of Equine Disease Quarterly, funded by Lloyd's of London underwriters, brokers, and their Kentucky agents.

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