Kitchen Waste as Feed for Smallstock

Kitchen waste is often fed to livestock as a supplement to their diet. Depending on the nature of the waste, it can make a valuable contribution to the animals' diet. Care must be taken when feeding kitchen waste it as it can be a source of infection for the animals. In extreme cases, this can result in contamination of the meat or eggs produced and cause illness in people consuming the livestock products. In some countries, certain types of kitchen or catering waste are banned from entering livestock feed.

Hazards from Kitchen Waste as a Feed Source Kitchen Waste as Livestock Feed References and Further Reading

By its nature, kitchen waste is very variable and it is difficult to make any kind of estimate as to its nutritive value. However, it has the advantage that it is a feed resource that livestock are likely to find palatable and will derive some benefit from. It is also a resource that would otherwise go to waste. What it is made up of will of course be largely governed by the livestock keepers' own diet (for example, whether it is made up of leftover rice or tortillas will depend on what is the staple food of the livestock keeper). These leftover staples are likely to be starchy, and so will be a good source of digestible energy to the livestock. Care should be taken when feeding sheep and goats, however, because feeding large quantities of cooked cereal to sheep and goats that are not accustomed to it can cause bloat.

Vegetable waste, especially green vegetable waste, provides vitamins that are of particular value to pigs and poultry. Pulses and beans will also provide protein, just as they do for humans.

 

Hazards from Kitchen Waste as a feed source

The greatest hazard associated with feeding kitchen waste to livestock comes from feeding animal waste. Although this is likely to be an excellent source of high quality protein, the risks of transmitting disease are much greater when feeding animal waste. Where is is used it must be cooked thoroughly and should be fed fresh, as the risk of infection will increase significantly with storage. For more on animal wastes see the publication by Müller (1980).

In order that people who consume animal products produced from by-products and kitchen wastes can do so with confidence, it is important that there is an understanding of the dangers of using these materials and of the ways in which they can be made safe. In general, the potential for problems arising from contaminated feed are significantly greater with intensive production systems, and increase along with the competition for low-cost feed sources.

Plant material or by-products

Plant material is likely to form the greater bulk, or in some cases 100%, of kitchen waste. Plant materials can become contaminated with a range of chemical products dangerous to animals that consume them. Examples include pesticides used to control insects or plant diseases, as well as chemicals from poorly cleaned stores and transporting vehicles. The material may also become infected by coliform bacteria, including Escherichia coli. If the plant material is not used within a short time, it can be contaminated by toxins produced by moulds (e.g. aflatoxin and other mycotoxins). In most situations the main practical approach to controlling potential problems is to reduce contamination of plant products through careful management and storage and to monitor possible contamination on any waste materials used as a feed source before use.

Animal material or by-products

The primary by-products from animal sources (see Machin) that form the basis of concern for animal and public health include:

• Rendered meat- and bone-meals.
• Acid-preserved fish and carcass wastes processed by using added acids and acid produced by fermentation.
• Swill containing restaurant and canteen wastes, waste foods and waste pig and poultry carcass material.
• Faecal wastes and gut contents.

Of these, the latter two categories cover the majority of potential sources of contamination from kitchen waste.

For more on the use of plant and animal by-products, see the paper by Machin, or the section on Crop and Industrial by-products

Kitchen waste, particularly starchy staples such as leftover rice or tortillas, can be an important feed supplement for livestock. For example in northern Pakistan, kitchen waste is a component of feed during the winter (see Wright et al. 2002). However it is only one of a number of different feed items and kitchen waste on its own will not provide an adequate diet.

Kitchen waste is probably more commonly given to poultry, but again there is evidence to suggest that additional supplements are also required in order to provide increased production. In Kenya, studies by KARI indicate that indigenous chickens are reared under a subsistence system of production by 90% of rural households in Kenya. Though they largely scavenge for feed they contribute to more than 60% of the eggs and meat produced in the country. Indigenous chicken scavenge around household compounds, feeding on available resources and on household kitchen waste and residues from harvest. If free range birds are supplemented with kitchen waste, the chick survival rate increases from about 54% to 69% at 8 weeks. The survival rate is further increased and the chicks grow faster if kitchen waste is supplemented with additional protein.

KARI. Improved management of indigenous chicken.

Losada, H., Cortés, J., Vieyra, J., Arias, L. and Bennett, R. Suburban livestock rearing by smallholders in the backyards of Xochimilco in the south-east of Mexico City as an important strategy for sustainable urban agriculture. Urban Agriculture Notes.

Poynter, G. and Fielding, D. Urban livestock in Kumasi: Survey findings. www.ruaf.org/1-2/28-29.html.

Wright, I.A., Duncan , A.J., Clemens, J., Rahman, A., Raja, O., Gordon, I.J., Hester, A.J., Raffique, S.M., Atiq-ur-Rehman, Ali, F. and Baig, A. (2002). A systems study of livestock production in the Northern Areas of Pakistan. In, Proceedings of a BSAS meeting held in Merida, Mexico, in November 2002