The pelvic factors of the bitch are one of the important factors that cause dystocia in the bitch. Clinically, dystocia caused by pelvic factors can be divided into the following four situations: one is that the pregnant bitch has a history of fracture in the pelvis; the second is that the pelvic bone itself has an osteoma; the third is that the pelvis is deformed during development; the fourth is that the age is too young, the pelvis is not fully developed, and it has not yet reached sexual maturity. When dystocia occurs due to pelvic factors, animal B-ultrasound should be used to check its condition and estimate the degree of dystocia.

Uterine factors, uterine torsion. Uterine torsion refers to the change in the position of the longitudinal axis of the uterus during the bitch's pregnancy. When doing a birth canal examination, the animal B-ultrasound examination shows that the cervix is tightly closed and has obvious wrinkles. Clinically, torsion can be divided into two situations according to the direction: one is that the direction of the fold is from the upper left back to the lower right front, which is right torsion; if the fold is from the upper right back to the lower left front, it is called left torsion.

Degeneration of uterine muscle fibers. Pregnant female dogs have a history of caesarean section, which leads to uterine hyperplasia and deformation, and is diagnosed by animal B-ultrasound observation. In addition, pregnant female dogs suffer from endometritis. The degeneration of uterine muscle fibers caused by inflammation will cause the female dog's labor force to decrease, causing dystocia in clinical practice. In normal management, animal B-ultrasound should be used for examination.

The uterus ruptures. In the process of clinical treatment of dystocia, veterinary staff use a large amount of oxytocin, which makes the female dog strongly push, and oxytocin is often used without checking the birth canal of the female dog itself and whether the cervix is open, which will cause the female dog's uterus to tear or even rupture. It is necessary to perform Animal B-ultrasound examination after dystocia.

Abdominal factors are divided into three situations. One is that the female dog is older and the abdominal wall muscles are weak to contract during delivery; the second is that there is a hernia in the abdominal wall. When the female dog gives birth, the contraction of the abdominal wall will cause hernia pain; the third is that the diaphragm has a history of injury. These factors can cause contraction pain or contraction weakness in the female dog, resulting in dystocia, so it is necessary to use animal B-ultrasound examination frequently.