By N. L. VANDEMARK, W. J. MILLER, W. C. KINNEY, JR., CARLOS RODRIGUEZ,
and M. E. FRIEDMAN[A]
[A] This publication was prepared by N. L. VANDEMARK, Professor of
Dairy Physiology. Research reported herein was carried out
cooperatively by the senior author and W. J. MILLER, W. C. KINNEY,
JR., CARLOS RODRIGUEZ, and M. E. FRIEDMAN, formerly members of the
Department of Dairy Science.
The first announcement in 1951 of the successful impregnation of a cow
with bull semen that had been frozen stimulated much interest and
research in freezing as a method of preserving bull semen. Research
during the years following 1951 resulted in considerable progress and
success in using freezing as a means of holding semen for long periods
of time without loss of fertility.
Between 1952 and 1957, research on many aspects of the preservation of
bull semen at sub-zero temperatures was carried out in the Department of
Dairy Science at the University of Illinois. Many of these
investigations have aided in perfecting the freezing technique that has
been adapted for practical use. Some of these findings have been
published, but many items have gone unreported except for general
references at scientific meetings.
It is the purpose of this bulletin to bring together the results of
several experiments carried out in connection with the freezing of bull
semen and to present a practical freezing procedure based on the results
of these experiments and findings at other institutions. Persons
interested in the development of the procedures and the reasons why
certain steps are necessary in freezing semen will find the details in
the first part of this bulletin. Those interested only in the freezing
procedure may turn to page 35 where a practical method of freezing semen
is described.