156 DISEASES OF CATTLE. 



virgin, or unimpregnated, condition is of nearly uniform size from 

 before backward, the main part or body being from 1-J- to 2 inches 

 across, and the two anterior branches or horns being individually little 

 over an inch wide. Immediately after conception the body and one 

 of the horns begin to enlarge, the vacant horn remaining dispropor- 

 tionately small, and the enlargement will be most marked at one point, 

 where a solid rounded mass indicates the presence of the growing 

 embryo. In case of twins, both horns are enlarged. At a more 

 advanced stage, when the embryo begins to assume the form of the 

 future animal, the rounded form gives place to a more or less irregu- 

 lar nodular mass, while later still the head, limbs, and body of the 

 fetus may be distinctly made out. The chief source of fallacy is found 

 in the very pendent abdomen of certain cows, into which in advanced 

 gestation the fetus has dropped so low that it can not be felt by 

 the hand in the rectum. The absence of the distinct outline of the 

 vacant womb, however, and the clear indications obtained on external 

 examination through the right flank will serve to prevent any mis- 

 take. The fetus may still be felt through the rectum if the abdomen 

 is raised by a sheet passed from side to side beneath it. 



Still another sign is the beating of the fetal heart, which may be 

 heard in the latter half of pregnancy when the ear is pressed on the 

 flank in front of the right, stifle, or from that downward to the udder. 

 The beats, which are best heard in the absence of rumbling, are about 

 120 per minute, and easily distinguished from any bowel sounds by 

 their perfect regularity. 



DURATION OF PREGNANCY. 



From extended statistics it is found that the average duration of 

 pregnancy in the cow is two hundred and eighty-five days. A calf 

 born at the two hundred and fortieth day may live, and a case is 

 reported by Dietrichs of a calf born on the three hundred and thirty- 

 fifth day, and another by the American Journal of Medical Science 

 as born on the three hundred and thirty-sixth day. It is the general 

 observation that in the majority of prolonged pregnancies the offspring 

 is male. Lord Spencer found a preponderance of males between the 

 two hundred and ninetieth and the three hundredth days, but strangely 

 enough all born after the three hundredth day under his observation 

 were females. It might be reasonably inferred that while the pre- 

 vailing i endency is to carry the males overtime, yet that the smaller 

 and comparatively much less developed female sometimes fails to 

 stimulate the womb to contraction until very far beyond the regular 

 date. 



HYGIENE OF THE PREGNANT COW. 



Among domestic animals considerations of hygiene must be made 

 subservient to profit, and therefore the first consideration is not to 



