COURSE OF NORMAL BIRTH 63 



cervix uteri; following this, they assist in rotation of the 

 foetus. 



Stage of Expulsion. — Expulsive pains are strong, and their 

 intensity is greatly assisted by the auxiliary abdominal 

 muscles. The intermissions are here short. The muscles of 

 the vagina and vestibule contract reflexly, seen by the periodic 

 retraction of anus and vulva. Immediately after birth these 

 contractions decrease in intensity. 



Post partum stage expels the after-birth, they are less 

 strong and have long periods of rest. Normally, the abdom- 

 inal muscles are not concerned in the production of post 

 partum contractions, but occasionally the uterine contractions 

 are assisted by them. Especially are those cows exposed to 

 severe post partum pains which lie with the hind quarters 

 lower than with the anterior extremities. 



2. — Course of Normal Birth. . 



How do we know in the cow that birth is approaching? 



While dealing with the phenomena of pregnancy, I already 

 hinted at the fact that certain signs manifest themselves, 

 especially in the last month of gestation. The swelling of the 

 udder, beginning three to four weeks before birth, is one of 

 the most important symptoms ; also the nature of the lacteal 

 secretions indicates approaching birth. As long as the milk 

 is watery and thin, birth of the calf is not imminent ; but 

 when milk is whitish-yellow and colostrum-like, it soon 

 occurs. 



To define the time of birth is necessarily of great import- 

 ance to the stock-owner. With him it becomes a habit to 

 visit a cow about to calf every night before retiring, in order 

 to see whether she ought to be watched that night or not. 

 Many men become very accurate in this respect by practice, 

 but even the most experienced one will err. I myself have 

 seen a calf born within two hours, while a careful survey pre- 

 viously made did not indicate an immediate delivery. 



Experience teaches us that the end of gestation and the 



