Using Food Processing By-Products for Animal Feed

Prepared by:

Roger G. Crickenberger, Associate State Leader, Agriculture and Natural Resources

Roy E. Carawan, Extension Food Science Specialists

Published by: North Carolina Cooperative Extension Service

Publication Number: CD-37

Last Electronic Revision: March 1996 (JWM)

Recovering by-products for use as animal feed can help food processors save money while preventing pollution. Waste management and water quality have become key environmental and economic issues in agriculture and industry. Today's food manufacturers face increased waste management costs and tighter regulations than in the past. Effective ways of managing waste are important in maintaining water quality, ensuring food safety, and protecting the environment while maintaining profitability.

Offering by-products for use as animal feed is an economical and environmentally sound way for food processors to reduce waste discharges and cut waste management costs. Selling by-products can also produce additional revenue. Livestock producers can save money as well if by-products offer a less expensive source of nutrients than traditional feeds and if they support acceptable animal performance.

By-products Suitable for Animal Feeding

Many by-products can be fed to animals. Generally, by-products to be used as feedstuffs should be economical, dense in nutrients, and free of toxins or other substances that may be unhealthy for the animals. Table 1 lists some commonly available by-products that are used as animal feeds. They are categorized by the principal nutrients supplied.

Table 1. Principal Nutrients in Common By-products Used for Feed


Nutrient supplied     By-product

Protein ..............Brewer's grains
                      Distiller's grains
                      Cull beans
                      Feather meal

Protein and energy ..Brewer's grains
                     Distiller's grains
                     Corn gluten feed
                     Peanut screenings
                     Wheat mids

Energy ..............Bakery meal
                     Fat
                     Hominy feed
                     Snack food waste
                     Soft drink syrup
                     Soyhulls
                     Vegetable, fruit processing waste

Roughage sources ...Apple pomace
                    Corn cobs
                    Cottonseed hulls
                    Peanut hulls
                    Rice by-products

Factors to Consider in Selecting By-products for Feed

It is vitally important to determine whether the by-products being considered for animal feeds are appropriate to the needs and conditions of specific feeding situations. Many factors must be considered in evaluating the suitability of by-products as feeds. Some of the most important factors are discussed here.

Moisture content. Many by-products contain more than 75 percent water. These materials are not suited for feeding swine or poultry in confinement, where automated dry-feeding systems predominate. They are much better suited to dairy or beef feeding, where silage-based diets are mixed and fed daily. The dry matter content of material from some processing plants may vary 50 percent or more during a typical week's processing. Thus, careful monitoring of moisture content and frequent ration adjustments are needed to ensure that the animals achieve the desired nutrient intake. Moisture content is the factor that often determines whether the feeding of wet by-products is economical. It adds to the cost of transporting nutrients to livestock, and the purchase price must be adjusted to discount for high moisture content and moisture variation. Because of transportation costs, most wet by-preducts are fed in animal operations located close to the food processing plant.

Nutrient density. The unique advantage of many by-products is that they can be inexpensive sources of valuable nutrients needed by livestock. The greater the nutrient concentration in the dry matter equivalent of the by-product, the more valuable it is to a livestock operator. Energy, protein, minerals, and roughage are the most frequent nutrients or diet components supplied through by-products.

Waste stream composition. In evaluating a by-product for its potential as an animal feed, livestock producers must know more about the material than just its moisture and nutrient contents. To determine whether a material is appropriate for a particular animal feeding situation, producers should consider these other factors:

Target animals. In evaluating one or more by-products, livestock producers should ask these questions: Will the by-product supply needed nutrients more economically than other feeds? Will the animals consume diets containing the by- product? Are the characteristics of the by-product compatible with the other diet ingredients and the technical aspects of the feeding system? Is animal feeding and nutrition expertise available to help manage the feeding program so that the by-product can be used effectively?

Handling and processing. Most by-products are transported in tractor trailers capable of carrying 20 tons or more. However, the density of some dry by-products limits the amount that can be hauled on a trailer and may increase transportation costs. In any case, access with a tractor trailer is usually necessary when feeding by-products. In addition, storage facilities to protect the materials from the weather and prevent liquid runoff are needed. Because many dry by-products will bridge if stored in grain bins or tanks, they are often stored in commodity sheds (pole sheds covered on the top and three sides). The feeding system must be of a type that makes it easy to incorporate the by- product into diets

Volume of material. Large processing plants usually generate enough by-Foduct to ensure an adequate supply, even for large livestock operations. Before a manufacturer and a livestock Foducer enter into an agreement to feed by-Foducts, it is essential to determine the quantity of material available, the seasonality of the supply, the ability of the animal operation to use the available quantities, and whether feeding the by-products will benefit both parties. From the standpoints of nutrition, safety, and animal health, the inventory of by-Foduct should be turned over relatively quickly, usually within seven days for wet materials. Wet by-products may deteriorate and become contaminated with molds and mycotoxins if stored longer.

Regulations. Government regulations may be involved in marketing a by-yoduct for feeding to animals. Before marketing by-products, processing plant operators should contact the Food and Drug Protection Division at their state department of agriculture to determine what regulations, if any, must be considered. Feed definitions, labels and guarantees, transportation regulations, and other legal matters should be investigated before beginning the marketing program.

Cost versus benefit. Livestock growers can feed by-Foducts economically only if animals can gain weight or Foduce milk less expensively using by-products in the diet than if alternative feeds were used. It is important to seek the expertise of a nutritionist when determining whether this condition can be met.

Effects on feed consumption. Some by-products, because of their moisture or nutrient content, may limit consurnption of the diet, resulting in poor animal performance. One example of a nutrient imbalance causing low feed consumption and performance is the feeding of high-fat by-products. The fat may combine with the calcium in the diet to form insoluble soaps, resulting in a calcium deficiency and decreased feed intake. This Foblem can be overcome by adding more calcium to the diet. Fat alone, if it exceeds 10 percent of the diet dry matter, may restrict feed intake and performance.

Safety concerns. For by-products to be useful as animal feeds, they must not present safety or health Foblems to the animals nor present a risk of contaminating the animal product to be sold. In the production and utilization of by-products, all parties must take care to prevent contamination with pesticides, mycotoxins, and other materials that could be dangerous to the animals or contaminate the animal product.

Procedure for Evaluating a By-product as a Potential Feed Source

Food manufacturers may use different approaches to determining the potential of their by-products for use as animals feeds. Some may employ a by-product specialist, waste engineer, or other person with the expertise to assimilate the needed information. Others may have to rely on university or Fivate nutritional consultants, waste engineers, feed manufacturers, or livestock feeders. In most cases, the expertise of several specialists will be required to develop and implement a successful by-product feeding Fogram. Laboratory analyses will be needed to determine the amounts of moisture, crude protein, crude or acid detergent fiber, macro and micro minerals, and other nutrients present in the material. Laboratory tests may also be needed to verify that no toxins or other contaminants are present.

The flow chart in Figure I shows the key steps in evaluating a by-product as a potential feed source.

Figure 1. Procedure for evaluating the suitability of by-products for animal feed.

1. Characterize the by-product.

2. Review regulations (feed definition, nutrient guarantees, transportation, storage requirements, handling, feeding management).

3. Calculate the cost-benefit ratio for substituting the by-product for conventional feeds.

4. Describe quality control measures needed to avoid contaminants such as molds, mycotoxins, pesticides, and chemicals.

5. Develop a financial plan for marketing the by- product.

6. Develop a sales agreer ment and any other legal documents needed.

7. Develop a feeding program, including delivery schedule, rations, and special management requirements.

8. Maintain contact with the livestock producer.

Summary

Marketing by-products as animal feeds can help reduce pollution and minimize waste treatment costs. If by-Foduct recovery is feasible in a given situation, it is critical that the material be kept free of contaminants, that inventory (if wet) be turned over rapidly, and that moisture and nutrient content be as consistent as possible. With effective quality controls, many livestock feeders can benefit from using food processing by-products.
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
CD-37
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