8 



when proper measures for its prevention and suppression are not 

 taken. In the beginning, after the first case, new cases may not 

 appear for several weeks ; then, however, abortions begin to 

 occur more rapidly until finally normal births occur only excep- 

 tionally. After a time the disease dies down, abortions occur- 

 ring only rarely, the majority of the animals giving birth to full- 

 time calves until a stage is reached where abortion occurs only in 

 those animals which have been introduced from healthy herds. 



After a herd has become infected, the separation of the appar- 

 ently healthy animals which never have aborted, taking them to 

 a place which is free from infection, is clearly indicated. If this 

 cannot be accomplished, it is advisable to segregate the already 

 infected and suspected animals in a separate stable or, if this is 

 not possible, in isolated stalls in the same stable, and supply special 

 attendants for them. Thorough disinfection of the entire prem- 

 ises should be practiced, burning all contaminated litter, remnants 

 of feed, fetal membranes and afterbirths which may be in 

 evidence. 



It is the apparent establishment of an immunity in animals 

 affected with contagious abortion which has been made the basis 

 of the modern vaccine therapy in the control and eradication of 

 this disease. At the present time two vaccines are on the market 

 — one, a three-injection method, for the protection of the preg- 

 nant animal, the treatment to be finished before the fourth month 

 of pregnancy; and the other, a single-injection method for the 

 immunization of virgin heifers and non-pregnant cows. Suffi- 

 cient w^ork has not been done with them to establish definitely 

 their value, but their use appears to be the logical line of treat- 

 ment. It is, however, only in herds where complete breeding 

 records are kept that the best results will be obtained through 

 vaccination. 



The Division of Animal Industry keeps on hand large amounts 

 of both vaccines, which can be applied promptly where out- 

 breaks are reported. It is recomended that the immunization 

 of virgin and non-pregnant animals be practiced rather than the 

 treatment of cows already in the gestation period. 



Besides keeping on hand the biologies necessary in the treat- 

 ment of the diseases so far enumerated, this Division has on hand 

 supplies of canine distemper vaccines, equine influenza and 

 Hemorrhagic septicemia vaccines, mixed bacterial vaccines for 

 the treatment of wounds of various kinds, keratitis mixed bac- 

 terins for the treatment of pink eye in cattle and Metritis and 

 Mastitis mixed bacterins, also for cattle. These vaccines can be 

 supplied at short notice for use by the veterinarians connected 

 with this Department. 



