502 



CYCLOPEDIA OF LIVE STOCK AND COMPLETE STOCK DOCTOR. 



will occur, more particularly if the croup is largely developed, Avliicli it is 

 ill some foals. One haunch may pass into the inlet before the other, how- 

 ever, and thus facilitate the passage. 



AVith the cow the mechanism of parturition in this presentation i.s 

 similar to that in the mare, Saint-Cyr shows, from actual measurements 

 of cow and fcetus, that the head of the calf can easily pass into the inlet, 

 owing to its less diameter; and that the principal difficulty is encountered 

 by the foetal thorax, which is slightly larger in every sense than the inlet. 



The bicoxo-femoral diameter of the croup slightly exceeds the bis-iliac 

 diameter of the pelvis; but it is possible that the pelvis of the calf, being 

 more cartilaginous and supple than that of the foal, may be submitted to a 

 slight temporary compression. It is to be remarked, however, that the 

 progress of the calf through the pelvis must be more protracted than that 

 of the foal, owing to the greater length of the maternal pubic symphysis, 

 and the more considerable extent of the pelvic walls, as well as the peculiar 



FORWARD DEVIATION OF POSTERIOR LIMDS IN ANTERIOR PRESENTATION. 



curve in the floor of the pelvis; though these disadvantages are somewhat 

 compensated for by the greater mobility of the sacrum. And, as we have 

 seen, such is really the case, the duration of parturition being shorter in 

 the mare than in the cow. 



With regard to the other animals, the same remarks will apply. We 

 may just note that with the common-bred bitch, which has a more or less 

 elongated muzzle, when fecundated by a dog of the same conformation 

 and size, and which in due course brings forth from five to eight young, 

 there is usually no difficulty in delivery. The conical form of the muzzle 

 of the puppies, and the softness of their tissues, permits their entering 

 the inlet in this presentation and passing easily through it under the in- 

 fluence of the uterine and abdominal contractions. But when the bitch 

 is of small size, and is fecundated by a young, vigorous and larger dog, 

 and especially if the muzzle of either or both parents is short, then the 



