DYSTOKIA. 



In the preceding pages we have dealt with birth as it occurs 

 normally. While it is accompanied by pain and violent efforts 

 on the part of the mother, the act is natural and comparatively 

 safe for both the mother and the young. There is constant 

 danger that birth may become difficult or impossible, without 

 artificial aid, and when these difficulties arise we know the con- 

 dition as dystokia or difficult labor. 



Normally the obstacles to be overcome in expelling the fetus are 

 exceeded by the expelling powers of the female. The obstacles 

 to normal birth consist chiefly in the narrowness and undilated con- 

 dition of the birth canal as related to the size, form and presenta- 

 tion or position of the fetus. When any one of these impediments 

 becomes exaggerated iu any way, the obstacles to birth become 

 accentuated. Constriction of the cervix uteri, displacement of 

 the uterus by revolving upon its long axis, narrowness of the 

 vulvo-vaginal passage or other impediments may be met, which 

 render parturition difficult or impossible except by surgical aid. 

 If the fetus should be of abnormal size as related to the dimen- 

 sions of the birth canal, if it should be deformed or distorted 

 from disease or aberration in development, if its presentation or 

 position should be unnatural, or there should be present some 

 deviation of an extremity or other part of the body from a 

 natural attitude, the impediment to birth may be so great as to 

 render artificial aid essential. 



Accordingly dystokia may be divided into two fundamental 

 classes. 



1. Maternal dystokia dependent upon some defect, disease 

 or displacement of the maternal organs. 



2. Fetal dystokia due to some disease of, or to abnormality in 

 the size, form, presentation or position of the fetus. 



The occurrence of dystokia in our domestic animals depends 

 very largely upon species, being comparatively common in some 

 and comparatively rare in others. The cow readily takes the 

 first place in the frequency of dystokia, both of the maternal and 

 fetal types. Dystokia in the mare is not uncommon and takes 

 first place in gravity. The bitch, sow and ewe also suffer fre- 

 quently from dystokia. 

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