Carcasses

Program Contact: Tipton Hudson, County Director
(509) 962-7507 • hudsont@wsu.edu

What do I do with a dead cow, horse, pig, etc.?

Dead animals must be disposed of within 72 hours of discovery.  Options include burial, rendering, composting, natural decomposition, landfill, and incineration.  Of these options, burial, rendering, and composting are possible in Kittitas County.  Natural decomposition is legal on large properties or rangeland/forestland (see notes below).  Small calves or sheep and goats may be taken to the landfill, double-bagged, but no large animals may be committed to Kittitas County Solid Waste.  Open buring is not legal.

The exact regulations on disposal options can be found in the Washington Administrative Codes 16-25-025 and 246-203-121 .

The person responsible for disposal of a dead animal must dispose of it in a manner so as not to become a public or common nuisance or cause pollution or surface or ground water.

Note to horse owners:  Euthanized animals have to be buried or composted soon after death.  There is a significant lethal risk to all scavengers (including bald eagles) if they consume animal tissues, which retain the drug, within several weeks after death.

On-farm Burial

A person disposing of a dead animal by burial must place it so that every part is covered by at least three feet of soil; at a location not less than one hundred feet from any well, spring, stream or other surface waters; not in a low-lying area subject to seasonal flooding or within a one hundred year flood plain; and not in a manner likely to contaminate ground water.  In many areas of the Kittitas County Valley there are high water tables, within just a few feet of the surface.  It is not a good idea to bury livestock under these circumstances.

Natural Decomposition

Natural decomposition, or leaving an animal out for the coyotes and birds to clean up is only legal when the animal can be placed at least 1/4 mile from any well, spring, sinkhole, or body of surface of water such as a river, stream, lake, pond, or intermittent stream; 1/4 mile from any residence not owned by the owner of the dead livestock animal; 1/4 mile from any public roadway; and out of public view.  Much of the valley will not fit these criteria.  Burial, composting, or rendering are better options.

Pickup and burial service, rendering: Steve Depiro 360-420-1332

Composting

Composting dead animals is legal and provides an alternative to paying for disposal through a rendering or burial service.

There are a number of good reasons to consider composting mortalities.  Composting can prevent flies, scavengers, rodents, and odors associated with burial or the drag-and-drop method.  There is reduced risk to ground and surface water quality as well as increased on-farm biosecurity.  It is advantageous to recycle the nutrients from mortalities; composting can lower operational costs.  Composting is a more manageable approach to process large volumes of mortality material, such as in the event of a winter storm/ice event or toxicity problem during which multiple animals die.

Location is important.  Avoid sites with poor drainage, as well as any location within 300 feet of surface water and drinking water wells.  A site with 2-6% slope and no rocks is optimal.

Ingredients

  • Dead animal(s)
  • Bulking material such as chopped straw, sawdust, chopped hay, etc.  (Kittitas County Solid Waste has free chipped yard waste available at the transfer station to all county residents – call 962-7542 for more information).
  • Tractor with bucket or skid-steer for building and turning piles
  • Probe thermometer with 36″ stem (optional)
  • Logbook for recording start dates, temperatures, types of material, turning dates, etc.

Composting occurs most rapidly and effectively at a moisture level of 50-60%.  This is moist, but not so wet that water is easily squeezed from a handful of material.  The carbon to nitrogen (C:N) ratio should be 25:1 to 40:1.  Too much nitrogen will result in release of ammonia or water-soluble nitrates that smell and can leach to groundwater or runoff with precipitation to surface water.  Too much carbon results in inadequate microbial growth and slow composting.

A pile will typically be 6-8 feel tall with a base of 1.5-2x the height.  Begin with bulking material at 2-3 feet deep.  Place carcass so that all parts are at least 24 inches from any edge.  Lance the rumen to speed up decomposition.  Bury the carcass completely with bulking material, again so that all carcass parts are >24 inches from the edge.

Record temperatures and any observations weekly.  To kill bacteria and other pathogens, the internal temperature of the pile must reach 131ºF for three consecutive days.  After several months, turn and mix the pile – only large bones and some hair should be identifiable by now.  After turning, the internal temperature should rise again to at least 131ºF for three days.  Finished compost should not smell or have any visible trace of animal tissues.  Large bones will be brittle and can be put into the next pile.

For more detail, download the WSU publication “On Farm Composting of Large Animal Mortalities”, read the Department of Ecology online publication “On-Farm Composting of Livestock Mortailities”, or visit the WSU BioAg website.

Livestock Mortality Composting