HANDLING HOG CHOLERA IN THE FIELD 179 



will fail to develop so as to be fit subjects for 

 simultaneous treatment. In these herds, the only 

 effective plan we know of is to protect the pigs 

 with serum alone until they are old enough and in 

 proper condition to receive serum and virus. Un- 

 der ordinary conditions the pigs receive serum 

 alone when they are between three and six weeks 

 of age, they are weaned when they are about 

 eight weeks old and receive simultaneous treat- 

 ment two to four weeks later. It is best to cas- 

 trate them as sucklings. Under exceptional con- 

 ditions we are compelled to give more than one 

 dose of serum alone before the time is ripe for 

 simultaneous treatment, but an extra dose of se- 

 rum for a small pig is not expensive. 



We have used this general plan since 1912, 

 starting with several garbage-fed and cholera in- 

 fected herds in quarters that did not permit clean- 

 ing and disinfecting, and protecting all subsequent 

 litters of pigs, year after year, with losses from 

 all causes totaling considerably less than five per 

 cent. We know of several other veterinarians who 

 have obtained like results during a term of years, 

 and we do not know of a single instance where the 

 plan has been followed consistently and found 

 wanting. The preliminary doses of serum alone 

 are not necessary in all herds, but we may resort 

 to them confidently under conditions such as we 

 have described. 



