Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)


Animal Science


Experiments were conducted with yearling beef cattle and feeder lambs to determine the effects of adding 3% oyster shells or various levels of hay to an all-concentrate diet of rolled corn grain adequately supplemented with protein, minerals and vitamins A and E. Criteria used for evaluating diets with varying amounts of roughage included feedlot performance, carcass characteristics, rumen fermentation, digestibility and concentrate replacement value of hay. In experiments with beef cattle, steers fed an all-concentrate diet gained 1.30 kg. daily with 6.79 kg. feed required per kg. gain. Adding 3% oyster shells to this diet resulted in only small effects on daily gain, carcass characteristics or rumen fermentation. Concentrate requirements were reduced slightly, resulting in the oyster shells having a replacement value for concentrate equal to 0.5 unit per unit of oyster shells. Digestion coefficients were generally higher with the diet containing oyster shells. Alfalfa hay was incorporated into the all-concentrate diet at levels of 3, 10 , or 20 %. The addition of alfalfa hay resulted in a 15.4% improvement in grain with essentially no difference. (See more in text.)

Library of Congress Subject Headings

Animal nutrition
Beef cattle -- Feeding and feeds
Sheep -- Feeding and feeds



Number of Pages



South Dakota State University