Depending upon state regulations, the level of mortality expected, the amount of funds available and the permanence desired, different types of bins can be constructed.

Permanent bins

Permanent bins are a good choice for farms with large numbers of goats where the annual mortality would exceed the capacity of one to two compost piles. Permanent bins are the most expensive to construct but provide the most control over the composting process and, once built, can be used for many years. Construction begins with a concrete pad of sufficient strength for the equipment to be used in building and turning compost piles, usually a tractor or skid steer with a bucket. The concrete pad helps prevent runoff and liquid seepage into the ground and provides a good working surface. A graveled area surrounding the pad helps when working in wet weather.

A permanent mortality composting structure should be large enough to accommodate enough bins to compost expected annual mortality. At a minimum, this will be three bins; two working bins and a third bin to cure compost, store carbon source, or use as an additional working bin if needed. Permanent bins usually have a roof sheltering the pile from the weather allowing for better control of composting conditions. Should a roof not be constructed, covering bins with a tarp helps protect the pile from rainfall that could make the compost too wet resulting in poor decomposition and odor generation.

Individual bin size and number is dependent upon mortality estimates. Formulas are available to predict the number and volume of bins needed based upon the weight of average daily mortality calculated by totaling the estimated annual weight of dead kids, yearlings, and adults and dividing by 365. The average daily loss is then multiplied by a factor and bin volume and number can be determined. Interested producers should refer to Anon, n.d.; Glanville and Harmon, 2006; Glanville et al., 2006, and Mukhtar et al., 2004 listed at the end of this chapter. These formulas will work for producers with large numbers of animals but for producers with few goats, it is best to think of bin size in relation to the expected numbers of carcasses and their size. For example, a goat operation that expects losses of 3 to 4 adults and 8 to 10 kids annually will have a very small average death loss so as to make the calculations of bin size unrealistically small. In most cases, a simple three-bin system will be sufficient.

In general, bin width should be 6 to 8 feet (2 to 2.5 m) or 1.5 times the width of tractor or skid steer buckets used in constructing and turning piles. Bin depth should be a minimum of 6 feet (2 m) and is often equal to or greater than the width, up to 10 feet (3 m) depending upon expected mortality. Bin height should be 5 to 6 feet (2 m) to accommodate piles of layered carcasses. The front of the bin should be removable, such as wooden slats dropped into channels on either side of the opening, or hinged. A gate with mesh wire could be used to enhance air exchange. If the depth of the bin is sufficient, the bin front could be left open. Bin walls are commonly built from pressure treated wood. Spaces can be left between boards to encourage air exchange. Cement could also form the walls.

Many producers may not want to invest in building a new structure for composting. Alternative structures to house permanent composting bins include unused machine sheds, corn cribs, hoop houses, and other structures with concrete or packed surface floors and sufficiently high ceilings to allow the use of tractor or skid steer buckets.

Low-cost alternatives

There are many low-cost alternatives to construction of permanent structures that will serve producers with small herds and minimal mortality. These low-cost bins can be placed on a concrete pad should state regulations mandate, or on a soil base. Two wire stock panels can serve as a bin by shaping them in a circle to enclose a mortality compost pile. Eight wooden pallets on edge can be held in place by T-posts or wired together to make an easy, low-cost bin. Small individual or paired wooden bins can be built from treated lumber. Wire with small openings or unused chain link fence held in place by T-posts or wired to stock panels will help hold compost material in piles and prevent disturbance from wildlife and dogs. Three large, round bales can be placed to form a three-sided bin in which mortalities can be placed. Wire or pallet bins should be made so they can be easily opened to build and turn compost piles, as well as for removing completed compost.

For producers with small herds, two or three small wire, pallet, or individual wooden bins may suffice for mortality composting. Bins 6 to 8 feet in diameter can hold one to two adult goats and one to three kids, depending upon size, composted in two layers. Too small a compost pile will have insufficient insulating qualities and poor heat retention. The pile will not heat properly and composting will be slow. Avoid building piles less than 6 feet in diameter.

When building small compost piles in the open, the final covering layer of carbon source is piled into a cone shape to shed rainwater, preventing the pile from becoming too wet. A tarp tied to cover the pile is beneficial in areas with high rainfall or for solid-sided, single or double wooden bins where rain can be trapped along the walls. It is better to prevent a pile from becoming too wet than to try and dry a pile that has become too moist and is not composting properly.

Windrow systems

Farms with very large numbers of animals may wish to consider a windrow system for mortality composting. In this system, successive mortalities are added to the end of the pile made for the previous mortality. Usually, a portion of the covering carbon source material is removed and the carcass placed and covered. This continues until the row is considered complete. The pile is turned based upon the date of the last carcass placed in the windrow. Windrow composting systems require more management than regular bin composting. More information on windrow systems is contained in many of the resources listed at the end of the chapter (in particular Bonhotal et al., 2002 from the Cornell Waste Management Institute and Mukhtar et al., 2004 from Kansas State University).

Next
Module Home
Certification Table of Contents
Browsing Table of Contents