Utilization of Corn and Grain Sorghum Residues in Beef Cow Forage Systems

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Abstract
Weather is the most important factor in crop residue (CR) utilization by livestock grazing. Snow cover or muddy fields can lower fall-winter daily gain from approximately .23 kg down to zero or may result in weight loss. During open grazing of CR, dry gestating cows can more than maintain body weight early in the grazing period while selectivity is good. As quality of forage declines, cows respond to supplemental protein, and greater response is obtained with natural sources as compared to NPN. One hectare of cornstalks or grain sorghum stubble will provide approximately 4 to 5 AUM of grazing if weather allows. The utilization of CR in drylot is related to type of CR harvested and cow nutritive requirements. The most critical factor, however, is keeping harvesting, handling, storage, and feeding costs low enough to be competitive with other feed sources. Dry cows may consume 10 to 12 kg of CR (dry matter basis) with a weight gain of .10 to .23 kg per head daily. Cows grazing cornstalks or grain sorghum stubble will consume only 25 to 30% of the available residue in 80 to 100 days. Most CR mechanical harvesting techniques are able to remove only 50 to 60 percent of the material left following grain harvest. This relatively low removal rate is particularly true of corn residue because of the cob fraction which is almost totally lost during mechanical harvesting. Limited grazing after machine harvest of CR is possible. Much of the grain lost by harvesting equipment is still available to grazing animals. Livestock grazing continues to be the most economical method of CR utilization, however, harvested material can be used if properly supplemented. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.

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