Iowa Agriculture and Home Economics Experiment Station Research Bulletin


Several events during the 1970’s have indicated the need for improved knowledge of substitution or trade-off rates between forage and concentrates in beef cattle rations. Unparalleled wide swings in the prices of feed grains and forages have given rise to large fluctuations in the price ratios among feeds and between feeds and beef. These fluctuating price ratios have caused the profitability of cattle feeding to be highly variable. They also have caused considerable swings among feed-stuffs in the rations that are o f lowest cost for a given gain. During the period o f large world crop shortfalls and shortages of food for human consumption, there was growing interest in animal rations based more on forage and less on grains. Finally, certain evidence uncovered in the 1970’s suggested the possibilities of concave forage-concentrate trade-off curves in beef production.



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