The reliability artifacts of the sheep B-ultrasound instrument itself are mainly due to the nature of the ultrasound itself, which forms an additional part of the sonogram that is not the sheep's own.

The artifacts that may be affected by sheep B-ultrasound in early pregnancy examinations are mainly: reverberation and multiple internal reverberations. When the sound beam is incident vertically to the interface of the uterine wall, most of the sound energy is reflected back to the probe, and it goes back and forth between the probe and the interface many times until the sound energy is completely attenuated, which is manifested in the sheep B-ultrasound image as multiple equidistant echoes behind the target, and the echo intensity decreases successively. This situation has the greatest impact in the examination of about 30 days. The echo band that appears behind the uterine wall of the ewe will cover the echo image of the gestational sac, which has a low echo intensity, and lead to a false negative result. We rotate the probe or make the probe move laterally in the rectum and deflect the working surface to make the sound beam enter the uterus laterally to avoid the reflection of the sound beam. But sometimes we cannot get a satisfactory sound image (the uterus is a columnar body, and part of the sound beam can always be incident vertically).

The flap artifact of sheep ultrasound is that the flap is the sound beam outside the main lobe, which propagates radially around the main beam axis. It can also produce reflection and refraction, forming echoes superimposed on the sound image of the main lobe, which is "yarn-like" and affects the clarity of the sound image. Changing the position and angle of the sheep ultrasound probe can change or disappear this echo.

The acoustic shadow of sheep ultrasound is that the front tissue absorbs too much sound energy or the reflection is too strong, resulting in a lack of sound energy in the rear tissue, and the sonogram is shown as no echo. Because the intestine contains gas and liquid, its interface appears strong reflection in the sound image, which can easily hinder the presentation of pregnancy images. Fecal balls in the rectum can also produce this effect. Turn the sheep ultrasound probe to remove the fecal balls between the probe working surface and the intestinal wall. If there is difficulty, take out the fecal balls before checking.

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