Masters Theses

Date of Award

6-1965

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Husbandry

Major Professor

George M. Merriman

Committee Members

J. D. Smalling, L. L. Christian, C. S. Hobbs

Abstract

The calf crop represents the only source of animal income from the beef cow herd. Infertility or sterility in the bull can cause either reduction or complete loss of income from the herd for a given year. Thus two factors become important: 1. A study of those semen qualities which may predict the probability of a bull's fertility. 2. The avoidance of nutritional and management factors which might decrease bull fertility. Semen quality and characteristics have, in a number of studies, shown varying degrees of correlation to fertility. Since these characteristics will vary even between ejaculates from the same bull, they cannot be expected to give more than an estimation of the animal's fertility. The actual fertility can be proved only by breeding trials. Nevertheless, the study of these semen qualities and characteristics currently form the only basis for rapid prediction of the potential fertility of the bull. It also follows that a study of the influences which different types of management or nutrition may have on bull semen quality allow a rapid method of estimating the effect that management or nutrition might have upon the fertility of the bull. At the Tennessee Experiment Station, several management-nutrition regimes have been developed for beef bulls. It was the purpose of this study to determine the effects of these nutrition regimes on the semen collected by electroejaculation from Hereford, Polled Hereford, and Angus bulls. Conception rate studies were not made.

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