The probe of pig ultrasound is close to the abdominal wall during in vitro exploration, early pregnancy examination, the probe is facing the pubic anterior border, the pelvic cavity entrance direction, or the 45 degree angle obliquely opposite the upper side, the probe is close to the skin, and the front and rear and the upper and lower points are fixed. Fan-shaped scan, the action is slow. Early embryos are small in the first trimester, so be careful to slow down to detect them. Do not slide the probe on the skin and scan quickly. (The method of exploration can be flexibly applied according to the actual situation, in order to detect the situation inside the uterus. When the pig's bladder is full of urine, it blocks the uterus, causing it to be unable to sweep to the uterus or only to detect part of the uterus. Detect after the urine is finished.)