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Emergency Livestock Disposal Home
Project Executive Summary
Project in Detail
Draft Guidelines for Emergency Cattle
Mortality Composting
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RESEARCH METHODS
Windrow Construction
To evaluate the practicality of the proposed construction methods, test units are constructed using a tractor-mounted loader, just as they would be on a typical cattle farm.
As shown in the sketch above, each test unit is comprised of a two-foot thick absorptive base layer, a single layer of four full-sized cattle carcasses weighing 800-1300 lbs (purchased from the National By-Products rendering plant located in Des Moines, IA), and a layer of material (same as base material) sufficient to provide at least 18-inches of cover over the carcasses. Typical test unit base dimensions are 20 ft X 18 ft, as shown below, and initial pile heights are typically about 1/2 of the pile width.
As suggested by the sketches, construction is a relatively simple three-step procedure. During the first step, a 24-inch deep base layer is placed on the ground to absorb leachate. Leachate occurs whenever excess precipitation (beyond what can be absorbed by the cover material) seeps through and exits beneath the windrow. Leachate also can originate from the carcasses themselves which (like the bodies of all mammals) are approximately 70% water.
After the base layer has been placed, four cattle carcasses are positioned on top of it. For additional infomation on the instrumentation shown in the photos, see the methods sections on decomposition and soil/water evaluation.
During the final phase of construction, additional material is placed over the carcasses to absorb precipitation, retain heat and odorous gases, and reduce accessibility by insects, rodents, and predators. Typically the same material used for the base layer is used to cover the carcasses. For the test unit shown in this photo, however, the carcasses are first covered with manure, to simulate co-disposal of infected carcasses and manure. A subsequent layer of ground straw was placed over the manure and carcasses to complete the test pile.
The final photo, below, shows six newly constructed test units (containing 24 carcasses) completed on November 11, 2003. The protruding tubes (which will be cut off at the surface of the piles) are for thermocouples that will be inserted into the piles to monitor internal temperatures.
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In Brief
- To evaluate the practicality of the proposed emergency composting system, field research test units are constructed using materials (silage, ground cornstalks, ground hay), and equipment (tractor-loader) typically available on most cattle farms.
- Typical windrows containing two rows of full-sized carcasses are approximately 18 feet wide at the base, and have initial (prior to settling) heights of 7-8 feet.
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