268 Veterhiary Obstetrics 



as to prevent the entrance of the penis. In one case which we 

 observed in a mare, a foal became impacted in the passage during 

 the night and remained until the following morning. The pres- 

 sure upon the vulva was so great that gangrene of the vulvar 

 lips ensued, resulting eventually in such a constriction of the 

 vulvar opening that copulation was impossible. 



We may rarely be able to ov^ercome such strictures by surgical 

 means, but as a rule they are not subject to remedy. The possi- 

 bility of such stricture should always be borne in mind in dealing 

 with inflammation of, or injuries to, these parts in female breed- 

 ing animals. 



13. Horizontal Position of the Vulvar Opening.* 



When breeding females, especially cows and mares, become 

 aged and their abdomens enlarged and pendulous, the pelvic 

 organs drop forward and downward, and, dragging upon the 

 anus and vulva, cause a more or less deep excavation in 

 the perineal region. At the same time the posterior dorsal 

 and lumbar portions of the spinal column become depressed, 

 producing what might be termed senile lordosis, or "sway back." 

 The lumbo-sacral articulation becomes involved in the change 

 of position of the parts so that it becomes depressed along with 

 the .sacro-iliac articulation, which brings about a relative eleva- 

 tion of the ischiatic tuberosities and a more nearly horizontal 

 position of the pelvis. 



These changes in anatomical relations modify the direction of 

 the vulvo- vaginal canal so that, instead of the vulvar opening 

 being approximately perpendicular, as in the normal, it ap- 

 proaches closely to the horizontal. In copulating, the penis 

 tends to approach the vulvar opening in a direction acutely ob- 

 lique, or well nigh perpendicular, to the long axis of the vulvo- 

 vaginal canal, thus rendering successful copulation uncertain, 

 since the penis tends to glide forward and slightly upward over 

 the vulva, against the anus, tail, or other parts. 



We have already drawn attention on page 50 to the danger of 

 physical injuries, against which we .should guard, but it is also 

 important to bear in mind that, whether such injury occur or 



Zschokke, die Unfruchtbarkeit des Rindes, page 134. 



