254
ABSTRACTS
yield. Now, bulls notoriously possess sweat glands, so might it not be possible to judge
their innate dairy worth in some such fashion ? That would take us a certain distance,
though not the whole way, towards revealing the bulls endowment for milk, and would
help us to pick out bulls hopeful for commercial purposes and promising for progeny
testing. [R. L. K.]
Artificial insemination in livestock breeding. W. V. LAMBERT AND FRED
F. MACKENZIE. U. S. A. Deptt. of Agriculture, Circular No. 567
T HIS article deals in detail with the advantages of artificial insemination in all
classes of domesticated animals and the development in the methods of application of
its technique to animal breeding. Although various obstacles stand in the way of the
extensive use of artificial insemination, the studies by various workers in Russia and in
other countries reveal that the careful coordination of the collection, despatch and use
of semen and the use of improved methods of preservation and despatch by sea or air
have brought within the realm of possibility the application of insemination to a large
number of distant herds. A ram's semen shipped from England to Poland was success-
fully used in impregnating ewes after 27 hours, and in the Argentine the successful im¬
pregnation of a cow was obtained after the seventh day of the collection of semen. Soviet
workers report that in 1935, 15,000 ewes were inseminated by a single ram, with
an average percentage of conception of 96.6. It is also stated that the percentage of
conception of 50 to 60 in mares through normal mating can be raised to a great extent
by bringing about artificial impregnation when the chances of conception are the
greatest, i.e. a few hours in advance of ovulation. In America the significance of this
operation in animal breeding has been understood by many agriculturists and dairy
owners. Many of the recently organized Cooperative Dairy Breeding Associations
whose main object is to obtain for their members the services of proved sires at a reason-
able cost, strongly advocate the use of artificial insemination. The operation is carried
out by skilled veterinarians. The chief factors of importance for the successful use of
this method in these breeding associations are a sufficient number of animals in the
associations justifying the purchase of superior sires and a sufficient number of females
to be inseminated, so that the operation can be easily performed without any
wastage.
Various advantages of artificial insemination have been enumerated. It is not
only described as an available means of making the fullest use of proved sires of all species
whose reproductive life is generally short, but also as a means of solving many problems
of breeding arising out of anatomical defects, age, difference in size and monogamous
species.
It must be emphasized that a successful operation demands great skill, care,
technique and thorough knowledge of the anatomical structure of the genital organs and
the physiology of the oestral cycle.
Two distinctive operations are involved in the process of artificial insemination.
The first is the collection of semen from the male and the second is the insemination of
the female. Of the various methods employed in the collection of semen, the one by
means of an artificial vagina has come into extensive use in large-scale operations, es-
pecially in Russia. The apparatus consists essentially of a thin rubber tube kept warm
by a jacket of warm water or air. The outer casing of heavy rubber, glass, ebonite or
metal has an inner sleeve attached in such a manner that a watertight space is created
between the two cylinders. One end of the inner tube is open to receive the semen
from the male and the other end tapers into a graduated glass container. The tempera-
ture of the water in the jacket is maintained at 38°-41°C. and the aperture of the
inner tube, after proper lubrication with gum Tragacarth in glycerine, is so regulated
as to afford adequate pressure and warmth to the penis of the male. By this method,
practically the entire ejaculate free from extraneous secretion and in sterile condition
is obtained. The chances of the spread of diseases such as Trichomoniasis, etc. are con-
siderably reduced and the sperms remain viable for a longer period. Artificial vaginas
can be used with sires of all species.