Thesis - Open Access
Master of Science (MS)
The selection for certain inherited characteristics war practiced approximately 2000 years before the Christian Era. Jacob (Genesis 30:28-43) was given all the speckled cattle in his master’s herd for being herdsman. In a few years, by selecting for the spotting factor, only speckled cattle remained in the herd. Selection was the first tool for segregating definite characteristics. As a means of more rapid improvement artificial insemination was practiced by an Arabian chieftain as early as 1322 A. D. (35). Since 1322 these crude methods of transferring semen have been perfected until approximately four million cows were inseminated in the United States during 1951. Investigators are constantly searching for new, faster, and more accurate methods for breeding livestock. Therefore, a method of using outstanding cows, similar to the method of using proven sires, in artificial insemination is the ultimate aim in this field of research. In 1890 Heape demonstrated the possibility of transferring the fertilized mammalian ovum from one rabbit to another (22). The possibility of increasing productivity of the cow by this means went unchallenged until 1949 when at least two independent investigators succeeded in isolating the fertilized ovum from the living cow (13) (43). Since this time one calf has been born through ovum transfer (45) (46). Most of the earlier experimental investigations dealt with surgical techniques which have certain disadvantages. If the transfer of ova is to become practical; simple, non-surgical techniques must be employed.
Library of Congress Subject Headings
Includes bibliographical references (pages 40-43)
Number of Pages
South Dakota State University
In Copyright - Non-Commercial Use Permitted
Graham, Edmund F., "Some Mechanical and Horomonal methods of Dilating the Bovine Cervix" (1952). Electronic Theses and Dissertations. 1242.