Sig7is of Pregnancy 387 



is of a moderate character, that is, if the load to be drawn or 

 carried, or the pace which is to be maintained, is not extreme. 



Physical or Objective Signs. 



The most important physical signs of pregnancy are those 

 indicated by a change in the volume and form of the abdomen 

 and mammae, accompanied by the secretion of milk, to which 

 may also be added, according to some investigators, a change in 

 the composition of the urine. 



The development of the fetus with its membranes and the con- 

 tained fluids, along with the increase in the volume of the uterus 

 itself, necessarily leads to a corresponding increase in the volume 

 of the abdomen. This increase naturally occurs chiefly during 

 the later stages of pregnancy, although it begins very early in 

 gestation. During these earlier months the apparent increa.se 

 in the volume of the abdomen must be due to an increased 

 volume of fat or of intestinal contents, since the actual increase 

 in the size of the gravid uterus is not sufficiently conspicuous to 

 bring about any visible changes. Later, this change in volume 

 becomes more marked and there ensues also some degree of 

 change in form, which serves to distinguish the enlargement of 

 pregnancy from other abdominal enlargement. 



The pregnant uterus, having a very high specific gravity, 

 drops directly upon the abdominal floor and bears it down, which 

 causes the abdomen to enlarge chiefly in the lower part, while 

 the upper portion apparently sinks somewhat. 



While this symptom is important as an indication of pregnancy, 

 it is not reliable. The enlargement is frequently not prominent, 

 so that in some cases, especially in mares, there may be so little 

 increase in the size of the abdomen as to wholly- deceive the 

 owner until near the time of parturition. 



On the other hand, various diseased conditions may give rise 

 to an enlargement of the abdomen which may closely simulate 

 pregnancy, such as dropsy or tumors of the ovaries, uterine 

 tumors, hydrometra or pj'ometra, ascites, and dropsy of the 

 kidney (hydronephrosis) and other abdominal organs. Even 

 in health, some females, especially the large herbivora, acquire 

 a very voluminous abdomen from feeding heavily on hay or 

 grass, and the condition at times so closely simulates pregnancy 



