174 BOYINE OBSTETRICS 



We have seen that dilatation of the cervix uteri during 

 natural birth was produced by two factors — contractions of 

 the uterus and pressure of the water-bag from within the 

 uterus. The former dilates the cervix somewhat and as a con- 

 sequence the accessory placentae become detached around the 

 internal uterine opening, so that the separated chorion is 

 driven against the internal opening of the uterus by the uterine 

 contractions. The folds in the cervical canal run from before 

 to behind, so that dilatation must take place from within the 

 uterus, and not vice versa. 



When the os uteri is opened a little by the earlier pains, 

 further dilatation is affected by the water-bag. Should the 

 cervical canal remain closed on account of the spasm, the 

 second factor remains useless and dilatation of the cervix with 

 the finger is rendered difficult on account of the anatomical 

 arrangement mentioned above. Should the spasm subside 

 after the uterus is exhausted (atonia uteri) the second factor of 

 mechanical dilatation is wanting. 



Symptoms. — The veterinarian is usually called after the act 

 of parturition has persisted for some time and the owner's 

 patience is exhausted, as neither the water-bag nor " waters " 

 appeared. The ligaments are depressed, the udder full, the 

 vulva cedematous; in fact, approaching birth is announced. Even 

 strong pains have been noticed. On exploration, the vaginal 

 portion of the uterus is distinctly felt, but the cervix is closed. 

 The calf in consequence of the uterine contractions and difficult 

 placental circulation, may be dead, but usually is alive. Boring 

 movements with the finger in the cervix are not very successful, 

 as one or two fingers may be introduced after a great deal of 

 trouble. 



The rape utics.— The activity of the abdominal muscles in 

 spasm of the cervix is much more intense than the pains. To 

 all appearances the cow is able to strain violently, while the 

 uterine contractions are in fact weak. When premonitory 

 symptoms are present, the ligaments sunken, the udder filled, 

 the vulva swollen, assistance must be rendered immediately. 

 As a rule, already the owner waited too long. 



