Masters Theses

Date of Award

12-1963

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Husbandry

Major Professor

O. G. Hall

Committee Members

C. S. Hobbs, J. K. Bletner

Abstract

A major portion of the cost of production of animal foods is attributed to the costs of feeding in the livestock industry today. Thus, much of the recent research in animal nutrition has been directed towards the discovery of new principles which may enhance the efficiency of utilization of feeds that are commonly fed to livestock. Herbivorous animals, particularly ruminants, are capable of utilizing large quantities of high cellulosic feeds due to the existence of symbiotic microorganisms in their alimentary canal. Rumen microbial digestion is, therefore, of great importance in the nutrition of cattle and sheep by enabling these animals to live mainly on roughages. The recent concept that ruminant nutrition essentially rests on microbial nutrition has promoted numerous investigations during the past twenty-five years concerning the factors which stimulate rumen microbial activity. A better understanding of the conditions which promote the activity of rumen microorganisms may enable us to make the most effective use of poor quality roughage commonly available on many farms. The determination of the various factors that affect the efficiency of digestion in the rumen has largely been achieved through numerous dji vitro studies in the laboratory and with the use of animal feeding experiments. In vitro studies with the so-called "artificial rumen" usually precede the conventional, more laborious, and costly feeding experiments with animals. These investigations have shown that rumen bacteria need specific nutrients at optimum levels for their maximum development and activity. Thus, it is obvious by now that ruminant nutrition largely rests on the nutrition of the symbiotic microbial population that exists inside the rumen. The extent to which the consumed food promotes rumen microbial activity largely determines its feeding value to the animal. The proximate nutritional factors involved in the maintenance of an active microbial population in the rumen are; (1) a source of readily available energy, (2) a source of nitrogen, and (3) minerals. In addition to the above factors, several substances have been observed to stimulate rumen microbial activity in vitro. The chemical identity of the factors involved in the above substances largely remains obscure; and, as such, they are classified as "unidentified factors." Some of these unidentified factors have been shown to occur in protein materials. Most often investigations in this field of study have been performed in vitro and require confirmation as to their beneficial effect in practical livestock feeding. With this objective in view, experiments were designed to test and verify the effect of feather meal hydrolyzate on the digestibility of an oat hay by rumen microorganisms in vitro and by mature wethers. Previous studies have indicated that feather meal hydrolyzate is a good source of unidentified factor(s) for rumen bacteria but results of studies to deter mine the beneficial effects of this same material on sheep and cattle performance have been inconclusive.

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