Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Animal Science


Even though growing and finishing beef cattle have been fed satisfactorily on all-concentrate diets, in many instances weight gains have been improved and management problems reduced by including some conventional form of roughage in the diet. The most efficient level of roughage will likely be a variable factor depending upon a number of things including weight and condition of the cattle and. nature of the roughages and concentrates. It is a well-established fact that .as the energy content of the diet increases the rate of gain increases and the feed required per unit of gain decreases. In addition to rate and efficiency of gain, a feedlot operator must also consider the cost of the grain. A diet that produces the most rapid gain does not necessarily produce the most economical gain. Less cost may result from feeding of lower energy feeds which may not only cost less per unit of weigh but also less per unit of energy as compared to higher energy feeds. Energy consumption depends on the amounts and kinds of feeds consumed, or generally in the case of ruminants, the ratio of concentrates to roughage. Ratios of concentrates to roughage in diets for finishing beef cattle has been the subject of considerable research in the past. Renewed interest in this area has resulted from changes in feed preparation methods, feeding practices and type of diets fed. These factors have been shown to influence the relative value of concentrates and roughages when fed in varying proportions. In a previous experiment at the South Dakota Experiment station (Larson, 1969), weight gains were improved by adding chopped alfalfa hay to an all-concentrate diet composed of corn and supplements. There were essentially no differences in weight gains between levels of hay at 3, 10 or 20% of the diet. However, total feed intake increased with increasing levels of hay resulting in a decrease in concentrates saved per unit of hay as the level was increased. The lower level of hay resulted in a more favorable response than did an equal weight of outer shells. Research with low levels of roughage and with roughage substitutes in cattle diets raises some questions regarding the role performed by the roughage and the importance of its physical form when making up only a small percentage of the diet. The experiment reported here was designed to compare the value of a low level of alfalfa fed in various forms in a corn diet supplemented with protein, minerals, chlortetracycline and vitamin A.

Library of Congress Subject Headings

Alfalfa as feed
Cattle -- Feeding and feeds



Number of Pages



South Dakota State University