GESTATION AND LACTATION 67 



heat for thirty days, she is probably safe in foal. The heat 

 period in the mare persists for several days, and therefore a 

 reappearance of evidences of heat shortly after breeding 

 should not be regarded as significant. It is pointed out 

 elsewhere that mares may sometimes come in heat and 

 conceive again (see superfcetation), even though already 

 pregnant. It is also true that some mares will persistently 

 refuse the horse, even though not pregnant. In the cow 

 a period of sexual quiescence for three weeks following her 

 breeding with the bull is good evidence that she is safely 

 " settled " and in due time will give birth to offspring. 



The beginning of pregnancy in an animal is often 

 accompanied by a marked change of temperament. A 

 nervous, excitable mare may become more gentle and 

 docile. It is also true that some mares which when 

 not pregnant are quiet and gentle with other horses 

 become cross during pregnancy and evince a desire to 

 fight other horses. This tendency increases as preg- 

 nancy advances. Following conception the pregnant 

 animal shows a tendency to lay on fat much more rapidly. 

 Feeders sometimes take advantage of this tendency to 

 finish heifers and sows rapidly for the market, but such 

 a practice is to be condemned, as the meat from pregnant 

 animals is less desirable for human food. As pregnancy 

 advances, the abdomen becomes larger at the sides and 

 below and the flank falls in. The loins become depressed, 

 owing to the sinking of the spine due to the increased 

 weight of the abdomen. This depression of the loins 

 gives the croup bones the appearance of rising. The 

 udder of the pregnant animal is not materially changed 

 during the initial stages of gestation, but during the later 

 stages this organ gradually expands and the teats become 

 larger. A short time before parturition the udder be- 



