DIAGNOSIS OF PEEGNANCY 35 



asymmetric. This asymmetry is also seen in some diseases, 

 and will be discussed in the differential diagnosis. Toward 

 the end of gestation, when the pregnant uterus occupies a great 

 portion of the abdominal cavity, the right lower abdominal 

 region bulges out materially, the flanks fall in, and the contour 

 of the last ribs, transverse processes of the lumbar vertebrae and 

 sacrum become plainly visible. As a result of the expansion 

 of the belly, the diaphragm is crowded upon during inspira- 

 tion and costal respiration the result, and the thorax expands 

 more while the abdominal muscles participate less in respira- 

 tion. This is plainly visible in old cows; they turn the 

 elbows outward to get the assistance during respiration of 

 certain muscles common to the anterior limbs. 



Although the increased size of the belly makes pregnancy 

 a reasonable, it is nevertheless not a positive indication; 

 therefore, mensuration of the circumference of the belly is 

 of no value. 



The cow during the period of gestation yields a consider- 

 able amount of milk. On the one hand, more food is taken in 

 to nourish and develop the foetus; on the other, many con- 

 stituents leave the body in the form of milk. The milch cow 

 has been bred for generations with a view to produce a great 

 milker, and has about reached in that respect the physiological 

 limit. There exists, as Stockfleth put it rightly, a competition 

 between the uterus and udder. Stockfleth deducts from this 

 that when the latter is victorious the former succumbs and 

 abortion tnkes place. He believes, therefore, that this physio- 

 logical relationship ought to be looked upon as a predisposing 

 factor in the frequently occurring abortion of the cow. 



In the milk cow, the udder at times swells several weeks 

 before the calf is born. After birth milk secretion rises to 

 a certain degree, remains constant, and decreases about two or 

 three months before the end of pregnancy. The time between 

 cessation of lactation and birth is the period of dryness. Its 

 duration may be very variable. Some owners do not wait for 

 the time when the milk secretion stops, but discontinue milk- 

 ing sooner and dry the animal off. They insist that in this 



