Techniques to manage the environmental impacts of cattle feedlots
As a cattle feedlot operator, you must take steps to make sure your business minimises its impact on the surrounding environment and community. Key issues are waste and odour management.
Manure removal for cattle feedlots
Cattle in feedlots produce 1t to 2t of manure per head per year. Efficient manure removal is important to minimise cost.
Guidelines for removing manure
You can remove manure directly from the pad if the manure pack is 100mm deep or deeper. Usually, you would use a front-end loader, scraper or grader for primary yard cleaning while you could use a bob-cat for cleaning around troughs and under fences. If the manure pack is shallow or hard, a light ripping may be needed to break it up before removal. You might also need to scrape the manure into a mound before loading. During the removal of manure, you should grade the pad to ensure that the surface is uniform and any potholes are filled in.
There is an interface layer between the base soil and the manure layer. It consists of mixed compacted soil and manure and is about 50mm deep. The interface layer forms an impermeable barrier, which prevents contamination of ground water by nitrates and salts in the manure. The interface layer must not be removed during yard cleaning.
You will not always be able to spread manure from the yards immediately onto land-use areas, so you must store manure appropriately, usually by stockpiling.
Stockpiling has certain advantages, including that it:
- allows yards to be cleaned out as often as needed, even when spreading machinery is not available or when agricultural land is not ready for the application of manure
- has little potential to pollute the local environment, if the stockpile is properly constructed and maintained
- allows for the decomposition of the manure, which reduces the amount of manure.
However, because stockpiling reduces the nitrogen content of manure, it makes it less valuable as an organic fertiliser. You should keep the amount of stockpiled manure to a minimum and you should use the manure should as soon as possible.
Guidelines for stockpiling manure
Add manure to the stockpile in thin, even layers. The layers should be dry (25% moisture content), otherwise spontaneous combustion may occur. Manure usually has a moisture content of 45% or less when it is removed from yards and is usually at least partly stabilised.
After you add each layer, compact the stockpile. This is particularly important if you want to stack the manure deeper than about 1.8m. Shape the stockpiles so that they shed rain. An even surface should be maintained by periodic grading to avoid ponding of water on the pile.
Stockpiles must be built within a controlled drainage area. This means protecting them from external run-off by drains and/or diversion banks. Run-off from stockpiles must also be controlled to prevent the run-off contaminating watercourses.
Feedlot managers can use changing weather conditions to reduce the impact of odour on neighbours. Activities that create odour, such as yard cleaning, should not be undertaken when atmospheric conditions will cause strong odours to remain undiluted. Bright sunny mornings are the best time to undertake these activities.
Odour release sites within the feedlot complex include:
- feedlot yards
- drainage system/ponding
- sedimentation basin
- retention pond - although chemical additives may help to reduce odour from this source
- silage pit/feed storage.
Areas and activities where the feedlot manager can control odour release include:
- yard cleaning
- sedimentation basin cleaning
- pond desludging
- manure screening
- manure spreading
- effluent irrigation
- disposal of dead animals.
The feedlot manager should only undertake controllable odour generating activities when weather conditions are least likely to cause odour to be carried to nearby neighbouring residents.
Resources to help you manage feedlots
Self-help resources are available for you to manage the potential environmental impacts of your business. These include:
- The National Guidelines for Beef Cattle Feedlots in Australia (PDF, 1.2MB) contains information on the establishment and operation of feedlots including the major design components of a feedlot, key site selection parameters, development application and approval process, and feedlot construction.
- The National Beef Cattle Feedlot Environmental Code of Practice (PDF, 450KB) addresses the environmentally relevant aspects of the site, design, construction and operation of a beef cattle feedlot. It defines a series of outcomes that should prevent or minimise adverse impacts on environmental values.
- The Feedlot assessment spreadsheet helps you to perform calculations for preparing permit applications, helps document feedlot design and management practices, and encourages more effective use of water and nutrient resources.
- The Sampling manual for environmental monitoring by intensive livestock producers (PDF, 210KB) explains the techniques for collecting and preparing samples for analysis to monitor the impacts from your feedlot.
Contact the Department of Agriculture and Fisheries (DAF) on 13 25 23 or email email@example.com for more information or to obtain a free copy of the feedlot assessment spreadsheet.