44 BOVINE OBSTETEICS 



the calf usually 39 weeks ; that is a few days less. Even here 

 one finds many exceptions. Generally, one imagines that the 

 mother carries a male foetus a little longer than a female one. 

 Also, the age of the mother, heredity and breed may influence 

 the length of the period of gestation. 



Literature gives several cases of abnormal pregnancy. 

 Servatius reports that a cow was pregnant for 391 days, 

 another 371, a third 400, and a fourth 376 days. Clarck 

 mentions a case where the period of pregnancy of a cow was 

 365 days, and where a living calf of extraordinary size was 

 born. Precocity also seems to have some influence. The 

 period of pregnancy in highly bred and early maturing breeds 

 is shorter (Wilhelm). 



8.— The Influence of Pregrnancy on Some Diseases. 



It is well known that pregnancy changes the course of 

 some diseases ; still, we do not know much about this. lu 

 man, this point is much more important, and its knowledge is 

 a great factor to the diagnostician. 



Many diseases run the same course whether an animal is 

 pregnant or not. Foot and mouth .disease seems to have just 

 as little influence upon pregnancy as it has upon the disease. 

 But experience teaches that pregnant cows, when suffering 

 with anaemia or hydrsemia, sooner succumb than in the un- 

 impregnated state. The morbid process is increased, as many 

 constituents, otherwise retained by the mother, are utilized to 

 nourish the foetus. 



Experience in numerous cases shows that cows with 

 certain symptoms leading with probability to a diagnosis of 

 tuberculosis, look better while pregnant, and apparently gain 

 flesh. After birth tuberculosis advanced with gigantic strides, 

 thus permitting it to appear as if tuberculosis during gestation 

 was latent. 



When osteomalacia occurs in the pregnant female, its 

 course is quicker and more serious than in the virgin state. 

 It is an old fact, that pregnancy and lactation hasten the 



