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free from vaginal secretions and uncontamina-
ted by extraneous matter, can be expeditiously
collected.
The Russian model A.V. consists of a hard
rubber cylinder, about 24 inches long, into
which is fitted a soft rubber tube or lining,
slightly thicker than the inner tube of a bicycle
tyre. The ends of the soft tube are turned
back on the ends of the outer hard tube and
fixed in position by binding with half-inch cotton
tape. The outer tube has a hole, fitted with
a screw stopper, through which water can be
poured into the space between the outer and
inner tubes, the amount of water being adjusted
to give the correct tension on the inner lining
A glass cup with a graduated stem fits into one
end of the A.V. and forms a receptacle for the
semen. In assembling the apparatus care must
be taken to ensure that this cup is firmly
secured, otherwise it may be dislodged when the
bull thrusts into the vagina. This is especially
liable to happen if there is too much water in
the A.V.
When assembling the apparatus care must be
taken to ensure that the inner lining and all
glassware are kept clean and dry. Before hand
ling the apparatus, the operator's hands should
also be clean and dry, and without trace of soap
or disinfectant.
For filling the A.V., water is heated to about
70° C. (160° F.) in winter and 60° C. (140° F.)
in summer, and then poured into the space be
tween the rubber liner and the cylinder.
Estimation of the correct degree of tension in
the apparatus is a matter of experience, but in
most cases this will be attained by laying the
A.V. horizontal and pouring water through the
filling-hole until the water is on the point of
overflowing. Insert the stopper and thoroughly
dry all parts of the apparatus with a clean cloth.
With a clean glass rod, smear a thin coat of
vaseline over the whole surface of the inner
lining. Excessive vaseline should not be used
as it may run down into the collecting cup and
contaminate the semen.
Insert a clean dry clinical thermometer into
the open end of the A.V. and leave it in position
while the glass cup is being secured. At the
time of use, the temperature in the lumen
should not be more than 45ºC. (112 ○ F.) nor less
than 42º C. (108º F.). As there is always some
delay between preparation of the apparatus and
collection, allowance has to be made for a slight
fall in temperature during this interval. This
will be greater in winter than in summer. The
A.V. may be insulated to prevent heat loss in
cold weather by enclosing it in a felt or cloth
jacket. If the temperature in it is allowed to
fall below body heat, a few drops of urine may
be expelled, and ejaculation may not take place.
3. THE TECHNIQUE OF SEMEN COLLECTION
(a) Place for collection—Assistance required
The collection should be made in a yard or field
with a level surface and a good foothold.
Concrete yards are not suitable owing to the
danger that the operator or the animals will
slip. It is an advantage if the same yard is
used for all services and collections so that the
bull becomes accustomed to the surround
ings and, when led into the yard, anticipates
service. In any case the work should only be
done where there is ample space for the operator
and his assistants to move well clear should the
cow turn. If the operation is carried out in a
confined place there is a risk that they will
be crushed, or the apparatus broken.
Bulls are handled as for controlled natural
matings and should be restrained by a pole
attached to the nose-ring. The preputial hairs
are usually very dirty and should be washed
with warm water otherwise the dirt may get
into the A.V. and contaminate the semen.
The washing and thorough drying of the pre
putial hairs should be done before the bull is
led out of his box.
The cow used for collection should, if possible,
be one in oestrus, and an old cow will usually
stand better than a heifer. Often, however, an
old quiet cow will stand and allow the bull to
mount, even though she is not oestrus; such
an animal will prove useful if it is desired to
make a collection when there is no cow in heat
available. The cow should be haltered and
loosely tied up.
Three persons are required, in addition to the
operator: one to lead the bull, and one on each
side of the cow to prevent her swinging round
when the bull mounts.
On some farms service crates are used for
ordinary matings but these are usually of a
design which is unsuitable for artificial collec
tion; it may, however, be possible to modify
existing crates so that they are suitable for this
purpose. Edwards and Walton (1938) have
described a special service crate for facilitating
collection and which may be used with a cow
not on heat. These are unnecessary in the
ordinary way, but they would prove of great
value when a large number of collections have
to be made at one centre.
(b) Collection of semen. When ready to
make the collection the bull is led directly
behind the cow. The operator follows the bull