NUTRITION
PIH-108
pork industry
PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA
By-products in Swine Diets
Authors:
Elwyn R. Miller, Michigan State University
Palmer J. Holden, Iowa State University
Vernon D. Leibbrandt, University of Wisconsin
Reviewers:
Vivian Baathe, Indianola, Iowa
Ted and Ann Diehl, Indianola, Iowa
James D. Green, Columbia, Missouri
Lynn A. Jones, Memphis, Tennessee
Ronnie L. Moser, University of Minnesota
Howard and Marilyn Tucker, Eden, Maryland
Feed costs comprise the major portion of the cost of pork production. While most of the feed for pork produced in developed countries consists of grains and oilseed meals, many by-products are supplied for swine diets by the industries in grain milling, baking, brewing and distilling, fruit and vegetable processing, and meat, milk, and egg processing. Many of these by-products are utilized regularly in manufactured feeds and supplements on the basis of their appearance in least cost formula specifications. Other by-products may be major ingredients in unique swine diets because of their abundant supply from nearby sources.

The purpose of this fact sheet is to identify by-products that are useful in swine diets, to describe how these byproducts result from processing, to present their nutrient value, and to show how they may be utilized in swine feeding.

Questions to Consider Before Utilizing By-products
A number of questions should be asked and answered satisfactorily before by-products are incorporated into swine diets.
1.	Are there animal and human health hazards associated with the by-products? Toxic substances, disease organisms, and growth inhibiting factors in a by-product should be checked. If present, the by-product should not be considered unless these deleterious factors can be eliminated or neutralized inexpensively.
2.	Is the nutrient composition suited to swine feeding? Check nutrient composition from feed composition tables and laboratory analyses. The by-product must be an effective source of available nutrients or energy to be con-
sidered as a substitute for conventional ingredients. Byproducts with low nutrient density and quality should generally be avoided, except, perhaps for gestating or open sows.
3.	Is the value of the by-product greater than the cost of incorporating the by-product into the diet? The major costs in the swine diet are for ingredients that provide energy, lysine, or phosphorus. If the by-product does not provide one or more of these nutrients at a competitive cost, it should be dropped from consideration. The major ingredients of conventional swine diets (grains and soybean meal) provide most of the requirements for energy and lysine (plus the other indispensable amino acids) and about one-half of the total phosphorus requirement. The by-product must replace a portion of these major ingredients without increasing cost to receive much consideration.
4.	Are there added costs of utilizing the by-product? By-products can directly increase costs because of added transportation, storage, processing equipment, facility modifications, or labor required for their use. Additional costs can result indirectly from reduced facility and equipment life, extra management time, feed wastage, waste disposal complications, increased risk of animal health problems, and reduced performance caused by by-product variability. Experience of others and accurate cost of production records for the existing feeding program are valuable tools when projecting costs.
5.	Do by-products reduce the cost of production most of the time? The financial commitment necessary to feed by-products requires a cost-benefit advantage a high percentage of the time, not just during periods of high prices of conventional ingredients. A study of the past price patterns for conventional ingredients is necessary for making wise decisions.
Cooperative Extension work in Agriculture and Home Economics, state of Indiana, Purdue University and U.S. Department of Agriculture cooperating. H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Purdue University Cooperative Extension Service is an affirmative action/equal opportunity institution.