114 Diseases of the Genital Organs 



amined in detail and certificates of pregnancy or non-preg- 

 nancy by a skilled veterinarian issued for each female. 

 Eventually, probably before most veterinary practitioners 

 are ready to render highly efficient service, buyers of ex- 

 pensive breeding cattle will demand reliable veterinary ex- 

 aminations as to sexual soundness. In the female assumed 

 to be pregnant, the prudent buyer w^ill place first reliance 

 upon the judgment of an expert veterinarian. 



The signs of pregnancy are many. Each has its value 

 and each is subject to certain limitations : 



1. The Failure of Menstruation After Copulation 



When conception follows coition,' estrum is rarely followed 

 by menstruation. If menstruation follows edition after 24 

 to 48 hours, the cow is probably non-pregnant. 



2. The Cessation of Estrum 



If a cow or heifer has been regular in her estrual periods, 

 and estrum fails to recur at the normal date, the animal is 

 quite probably pregnant. The probability is accentuated if 

 menstruation following coitus failed. The sign is of little 

 value in irregular estrum. The estrual period may be com- 

 paratively short or long, but in order to be of value in judg- 

 ing conception, the periods need to be alike. That is, one 

 animal may have an estrual cycle of eighteen, and another of 

 twenty-two, days but an animal having once an interval of 

 eighteen days and at another time a cycle of twenty-two 

 days offers suspicion of ovarian disease. The failure of an 

 estrual period in such an animal is not a good index of con- 

 ception. In healthy cows and heifers there is little varia- 

 tion in the estrual cycle in the individual ; the variation rarely 

 exceeds twenty-four hours. It is important alike for the 

 breeder and the veterinarian that accurate records be kept 

 for each heifer and cow. ^. 



Estrum does not always cease with conception. In my 

 judgment, one to two per cent, of pregnant cows and heifers 

 show estrum. In some of these, the estrum recurs at vary- 

 ing intervals up to the seventh or eighth month, but as a rule 



