Minimizing Starch Consumption by Finishing Pigs: Demonstrated and Theoretical Approaches

Peter. J. Lammers, Research Associate and Mark S. Honeyman, Professor, Animal Science


The connections and tensions among grain production, livestock feeding, and biofuel generation is well illustrated by conditions in Iowa during the early 21st century. Historically, feeding corn to livestock, particularly pigs, was the primary method for Iowa farmers to increase the value of their crop. Perennial surpluses of corn lowered market prices of the crop and encouraged development of other markets such as ethanol production. Industrial production of ethanol began in 1978 and has experienced exponential growth since 2002.   Production of ethanol from corn grain results in removal of the starch and concentration of the protein, lipid, fiber, and ash fractions of the corn kernel. Iowa leads the United States in production of corn, pigs, ethanol, and biodiesel. Accordingly, Iowa also leads the U.S. in the production of co-products of these industries – swine manure, distiller’s grains with solubles, and crude glycerol. The challenge for a successful swine industry is to create linkages that capture the advantages of each resource. 


The traditional conditions of abundant corn may not continue in the future. It is appropriate to discuss diets based on alternative energy feed sources for swine in Iowa, the leading corn, pig and ethanol producing state. Because starch is used to make ethanol from corn, the objective of this analysis was to explore swine diets that minimize starch usage.


Consumer demand and resultant market prices will ultimately determine whether corn is used for producing ethanol or feeding pigs. For each market pig fed a typical corn-soybean meal diet from 18–127 kg, 262 kg (10.0 bushels) of corn grain is consumed. Proven diets can reduce corn use by about 30% with theoretical diets potentially lowering corn use by 45%. Typical corn-soybean meal diets use starch to supply approximately 60% of the total NE. Proven diets can reduce starch use by 26% with theoretical diets potentially reducing starch use by 45%. Although some alternative feedstuffs can be incorporated into pig diets, the feasibility of expanding their use is uncertain. Effects on pork quality, feed delivery systems, feed storage and handling characteristics, and relative economics of alternatives remain to be explored further. Using bioenergy co-products can reduce corn feeding to pigs by 25% and has the potential to reduce corn feeding to pigs by about 35% to 45%.

This material has been presented in several scientific and animal production venues.


Swine diets can utilize more biofuels coproducts than are normally included in rations, in tradeoff with corn grain.

More inclusion of biofuel coproducts will alleviate some of the competition for corn between processing and feeding, and will reduce the transportation needs for hard-to-handle coproducts.

Less conflict between feed and fuel needs will allow both to grow at rates needed to supply world food needs and domestic fuel demands.


100 Corn and Soybean Production and Protection

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