By Blake Jackson
Corn silage is the most common roughage in U.S. feedlot diets because it delivers both fiber and starch. However, rising seed, nitrogen, and harvest costs encourage interest in lower-cost alternatives. Forage sorghum, known for drought tolerance and solid yields, is one option.
A Penn State study evaluated whether forage sorghum silage can replace corn silage in grain-based finishing rations when diets are balanced on an equal neutral detergent fiber (NDF) basis.
Crossbred beef × dairy steers and heifers were assigned to three treatments that differed only by roughage source: 20% corn silage (DM basis), 11% forage sorghum, or a blend of 10% corn silage plus 5.5% forage sorghum.
All rations used dry-rolled corn and were balanced for equal NDF and crude protein. Forage sorghum was cut, baled, individually wrapped, then ground before mixing; corn silage was bunker stored. These methods produced different particle sizes, which may have influenced rumen function.
Cattle fed forage sorghum alone or blended showed about 8% higher dry matter intake (DMI) than cattle fed corn silage alone. Average daily gain reached 3.96 lb/day with forage sorghum versus 3.78 lb/day with corn silage.
Despite higher intake and slightly higher gain, feed efficiency (feed-to-gain) did not differ among treatments. Over 120 days, forage sorghum cattle consumed roughly 265 lb more DM per head.
Cost of gain based on prevailing prices and Penn State Agronomy Guide estimates was similar: about $0.77/lb for forage sorghum diets versus $0.75/lb for corn silage diets, with actual costs dependent on yields, DM content, and corn grain price. Sorghum may also reduce costs through flexible harvesting methods.
Importantly, carcass outcomes yield grade, quality grade, and other measured traits were not different among treatments. This matters for feeders selling on grids or formulas where carcass results drive returns.
Bottom line: When rations are balanced on an equal NDF basis, forage sorghum silage can replace some or all corn silage in finishing diets.
Expect higher intake and slightly higher gains, with similar feed efficiency, comparable carcass performance, and costs that hinge on local agronomics and markets. Particle size and processing may affect rumen buffering and merit further study.
Photo Credit: gettyimages-awakr10
Categories: Pennsylvania, Crops, Corn, Sorghum