Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science


The transition to the pelleting of natural feeding materials has produced many problems. Various opinions have been expressed by the investigators regarding possible solutions to these problems. The proper mechanical formation of the pellet or wafer has been studied by several investigators. Several necessary factors have been determined. The temperature ranges that will produce the best possible product, from a feeding standpoint, have been tested against various pressures. The fineness of grinding or chopping have also been considered, as they relate to the digestibility and economy of the finished product. Moisture and adhesive agents have been considered in determining what level is optimum for pelleting or wafering. In addition to the mechanical factors, the actual composition of the product being pelleted must be considered. Cellulose and lignin, the most undigestible portions of plants, produce a direct effect on any results connected with digestibility. Any structural change brought about in either component would have a decided effect on its nutritive value. The investigators engaged in feeding trials are not in total agreement on the benefits of pelleting. The reasons for increased rate of gain cannot be satisfactorily explained. Increased consumption and faster digestion have been advanced as possible explanations. However, some workers suggest that increased gain is not due to feed intake alone. Another factor discovered by several authors is that the greatest advantage from pelleted roughage is derived from the poorer quality natural products. This concept suggests a change in the physical and/or chemical relationship between the natural and pelleted product. A complete analysis of the problems present too broad a field to be covered in a single investigation. It is the intention, therefore, of this study to explore some of the more basic aspects of the pelleting process. An attempt will be made, in this pilot study, to determine what changes take place in the material that would cause an improved feeding value to be derived from the pelleted product. These specific objectives, as they pertain to the pelleting problems, will be considered: (1) In vitro digestion trials, comparing the digestibility of high and low quality pelleted roughage to its unpelleted counterpart. (2) Comparing similar samples of roughage in the pelleted and unpelleted state by the use of an infra-red spectrophotometer to determine if a difference in basic structure exists. (3) “Proximate” and lignin analysis of the pelleted and unpelleted roughage to determine any changes in composition. (4) An examination of the crystalline structure by the use of x-ray diffraction to determine if any structural changes have resulted from the pelleting process. (5) An examination of the molecular linkage by a polymer process to determine if depolymerization occurs during the pelleting process.

Library of Congress Subject Headings

Pelleted feed


Includes bibliographical references



Number of Pages



South Dakota State University