PREVENTIVE MEDICINE 273 



ini; tlicir application to be practicable, if the severest restrictions 

 on movement, comprising compulsory isolations for long periods 

 of aborted animals and those still pregnant but known to be infected, 

 would accomplish eradication, for we know that cows may become 

 carriers of infection for a prolonged period during which the bacilli 

 may be excreted in their milk." 



The disease having appeared in a herd, much depends upon 

 the construction and arrangement of buildings for the prevention 

 of its spread. If isolation quarters are limited or entirely absent 

 it is almost hopeless to expect that its spread among the herd 

 will be prevented. However, every effort should be made in this 

 direction. 



Cows which have aborted, or which show signs of abortion, 

 should be placed as far from the rest as possible. Suspected cows 

 must be milked last, and separate grooming, feeding and drinking 

 utensils supplied. Attendants must disinfect their hands and wash 

 their boots after working among them. 



Discharges, foetus, membranes, and soiled litter must be burnt. 

 The genital passage of aborted cows should be washed out at least 

 once daily with a non-irritating antiseptic until fully a week after 

 discharge has ceased. The tail and hindquarters should be washed 

 with a disinfectant at least twice daily. Stalled cows should have 

 their tails tied so as to keep them clear from the fseces channel 

 when they lie down, and to prevent cows swishing them about. 

 After each cleansing of the faeces channel it should be flushed out 

 with plenty of water; this is easily accomplished without flooding 

 the liquid manure tank if a two-way pass is used (see p. 71). 

 Newly purchased cows should, if possible, be isolated until they 

 have calved clear of suspicion. 



Washing of the penis and prepuce of the bull should be practised 

 if the animal belongs to an infected herd or if it is used by neigh- 

 bours when the disease is suspected to be in the vicinity. 



One attack is followed by immunity. The majority of cows 

 do not abort a second time, and it is still more rare for a third 

 abortion to occur in the same animal. The disease in the herd thus 

 tends to wear itself out. In addition to the methods of isolation 

 and disinfection already described, measures of vaccination have 

 been introduced for the prevention and control of the disease, 

 and these have met with a very considerable amount of success. 

 Two kinds of vaccine have been tried in Great Britain, designated 

 Anti-abortion A. (consisting of living bacilli) and Anti-abortion B. 

 (consisting of dead bacilli). One dose of the former is given and 

 the animal is not put to the bull until at least two months after 

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