Early Pregancy Diagnosis - MS Schippers Pregtector Doppler Mode D'emploi

Place the headset comfortable on the top of the head
and cover the probe-face with coupling medium. Place
the probe on the sow's flank, in front of the leg, on the
belly, approximately in line with the second teat from the
rear. (see illustration). Direct the probe upwards,
imagining that the beam of ultrasound will pass trough
the centre point of the sow and emerge on the opposite
side of her backbone. The uterus runs roughly from front
to back, so a small vertical 'scanning' movement will
usually pass the sound beam over the uterus. On this
heavily pregnant sow, you probably hear the fast pulse of the umbilical cord, or even a fetal heart,
immediately the unit is switched on. Adjust the volume control for maximum comfort and clarity.
Listen tot these sounds recorded on the instruction cassette in order to be sure of recognizing them.
Having found one of them, search for the other by changing the angle of the probe.
Apply firm but not excessive pressure to the probe. One result of pressing too hard against the sow
is that she will be disturbed by this and move around more, causing unnecessary noise in the
headphones. In case of a sudden movement or other unexpectedly loud noise, immediately release
the on/off switch to silence the detector.
Be careful not the move the face of the probe across the sow's skin. This will cause noise in the
headphones and also remove the coupling medium from the probe. You can move the probe and
loose belly skin together and cove quite a large area of the abdomen without causing any noise or
losing contact. Should the probe become removed from the sow, either because you want to try
listening in a different site, or because movement of the sow has necessitated removal, you must
always re-apply coupling medium before replacing the probe. Coupling medium has the effect of
removing air from between the probe and the skin. Sound is absorbed by air, and the 'volume' of
the ultrasound being used here is so small that any air it passes trough will greatly affect the
performance of the instrument.
It may be difficult to find the uterine artery in this heavily pregnant sow, because it runs on the
upper surface of the uterus, which by now is swollen with its contents, and it could be beyond the
range of the detector. You could however try for a minute or two to find it. It will be clearly different
from the fetal pulses you have already heard because the sow's heart rate will be only about half
as fast as that of the fetuses. If you cannot find the sow's pulse, don't worry, as the uterine artery is
largely meaningless at this advanced stage of pregnancy, as long as you can hear one or more
fetal pulses. Carry on familiarizing yourself with the instrument for a while before moving to the dry
sow house te check a sow around the mid-point of gestation.
B) Early Pregancy Diagnosis
Although you can test sows from as early as 14 days after service or insemination, you first
attempts should be with sows around 6 weeks pregnant. Again, choose a lying sow to begin with
as this will make testing easier. Cover the probe with coupling medium and place it in the apex of
the triangle of belly skin, as illustrated. Don't turn on the PregTector until you are ready to listen.
When you do, listen for the whip-like, whistling, pulsing sound of the uterine artery. This will be
much slower than the fetal pulses you were listening to in the farrowing house, as is shown on the
instruction tape. Once you are sure that this sound is present, the diagnosis has been made. Now
move on to other sows, gradually testing earlier and earlier in gestation. You will quickly learn to
make a positive diagnosis, as the sound of the uterine artery is so distinctive. As you gain in
confidence, you will find that you only need to hear two or three pulses from each sow, and testing
will be very quick.
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