158 DISEASES OF CATTLE. 



are very exceptional cases in which the well-fed cow will accept the 

 bull weeks or months after actual conception, and others equally 

 exceptional in which the well-thriven but unimpregnated female will 

 refuse the male persistently, but these in no w^ay invalidate the gen- 

 eral rule. 



The bull, no matter how vigorous or how ardent his sexual instinct, 

 can not be made to pay any attention to a cow which is not in heat; 

 hence indications of pregnancy can be had from both the male and 

 female side. "\Mien she has conceived, the cow usually becomes more 

 quiet and docile, and lays on flesh and fat more rapidly, especially 

 during the first four months of gestation. The stimulus to digestion 

 and nutrition created by the demands of the growing fetus, added to 

 the quieter and more uneventful life, contributes to this result. Some 

 feeders avail themselves of this disposition to prepare heifers and 

 cows speedily for the butcher. 



The enlargement of the abdomen, and its dropping so that it bulges 

 below and to each side, while it falls in at the flank, between the outer 

 angle of the hip bone and the last rib, are significant features which, 

 though they may be caused by abdominal tumor or dropsy, are 

 usually marks of pregnancy. From the same increasing weight of 

 the abdomen the spine in the region of the loins sinks so that the 

 bones of the croup seem to rise, especially back toward the root of 

 the tail. In the early stages of pregnancy the udder develops slowly, 

 and toward its completion quite rapidly. For a long time there is 

 merely a sense of greater fullness when handled ; the wrinkles in the 

 skin become shallower and are effaced, and the teats are materially 

 enlarged. Beginjiing a few weeks after conception, this tends to a 

 steady development, though slight alternations in the sense of suc- 

 cessive gi^owth and shrinkage are not uncommon. In milking cows 

 this does not hold, as the milk usually tends to a steady diminution 

 and the udder shrinks slowly until near the completion of the period, 

 when it undergoes its sudden, remarkable development, and yields at 

 first a serous liquid and then the yellow colostrum, which coagulates 

 when heated. As pregnancy advances the mucous membrane lining 

 the vulva becomes swollen and of a darker, bluish-red hue; the 

 mucous secretion also increases, becoming very abundant just before 

 calving. When the feeding has not been altered or restricted, a steady 

 diminution of the salts of lime excreted in the urine is an attendant 

 on pregnancy, the lime being demanded for the growing body of the 

 fetus. 



After the fifth month the movements of the calf may often be 

 observed in the right flank, nearly in front of the stifle, when the cow 

 is drinking cold water. The sensation of cold on the side of the first 

 stomach, which lies to the left and directly below the womb (PI. I), 

 stimulates the calf to active movements. Avhich are detected on the 



