Considerations For Livestock Composting In SD

By Tracey Erickson

In any livestock operation there are always mortalities. So how do we properly dispose of those animal carcasses? Not everyone has access to a rendering service anymore, and if you are a sheep producer, rendering companies do not take sheep mortalities. So what options do we have outside the rendering service? I call it the “BBC”, either burn, bury, or compost. The latter is the point of our discussion.

Composting is just as much a science as it is an art. The science would be the decomposition of organic substances into a stable material in the presence of a carbon source, occurring aerobically (with oxygen) and producing NO unpleasant odors. The art of composting is the personal management brought into the process.

In South Dakota however, if you plan to compost some things need to be done first according to state regulations. A producer must obtain approval from the SD Animal Industry Board (SD AIB) by first submitting a composting proposal. To get approval you must set up your protocol outlining the design of your compost process and how you will manage your compost site. More information is available in the South Dakota Animal Industry Board Animal Composting guide.

So what things will you need to consider in designing your protocol and compost pile?

• Compost site and location
• Compost materials and ingredients
• Compost design
• Equipment Requirements

When choosing a site and location you should first consider…1. Locate your site away from water sources, such as streams, ponds, sloughs, lakes, and wells. 2. The site should be well drained and should not accumulate surface water. 3. You should consider its location relative to your livestock facilities for access year around. 4. It should be aesthetically pleasing. 5. Traffic patterns are also a consideration. You don’t want to be hauling your mortalities on a major road to your compost pile.

Secondly, what materials or ingredients are needed to start your compost pile?

1. A carbon source which could be any of these ingredients: sawdust, crop residues, chopped corn stover or old corn silage, cereal grain straw, cattle manure, and dried grass or yard waste. Ideally the ingredients should be about 50-60% moisture and of small particle size; however oxygen will still need to be able to penetrate into the medium.

2. A nitrogen source which is the animal carcasses, however, when starting a fresh pile you may need to add nitrogen in the form of ammonium nitrate.

3. Water should be available if the carbon medium is too dry and water would need to be added to get it to the ideal 50-60% moisture content. The optimal Carbon : Nitrogen ratio is 25:1. Please refer to the SD AIB Animal Composting pamphlet for appropriate mixing radios given the medium used.

Compost design is the third item to consider. Will your compost site be a mound, a roofed or an unroofed composter? The advantage of a roofed composter is less weather effects, worker protection during inclement weather, it is more aesthetically pleasing, and rodent control is more easily performed. Unroofed composters have the advantage of being less costly. In addition, concrete bases are optional. However, something to strongly consider is rodent or pest control, as you do not want animal parts being drug out by dogs, vermin, or other animals and left to lie all over the countryside. A fenced area helps this situation.

The last part to consider of your protocol design is your equipment. You will want to have either a tractor with a loader on it or a skid loader. This equipment will help facilitate working with the carbon source and handling the carcasses. You should also have a probe type thermometer at least 36” long and preferably made out of stainless steel so it will last. A manure spreader is needed for the disposal of your compost when the process is complete.

A logbook is utilized to record the number of animals buried, dates, weights, temperature readings and inventories. A moisture tester is useful to monitor the percent moisture in the pile. A moisture test can also be done in an old microwave reserved for this purpose if you have a gram or ounce scale. A water source should also be available. The “art side” of this process is the management of your pile. Some basic things to remember are that when you start a pile the ideal moisture should be between 50-60%.

If you start your compost pile in the winter, a fresh pile, it may not actually start composting until the weather warms. A frozen carcass will not start decaying until thawed, thus carcasses placed in a warm medium such as corn silage taken from a silage pile, will start degrading faster. In addition, finished compost can be used to help start a new compost pile. It helps get to the desired temperature faster along with getting the desired bacteria established faster.

Compost should have an internal temperature of 130 to 140 degrees Fahrenheit for at least 2-3 days. Mortalities should be added in layers and surrounded completely on all sides by at least one foot of carbon medium. You should prevent rodent problems from the start. You must commit to continued monitoring of the pile. And lastly, if there is putrid odor present in your compost pile something is wrong with the composting system!


Source:SDSU