418 Effective Farming 



at least three or four weeks following the treatment of healthy hogs 

 with serum alone. This immunity seems to last longer in old hogs than 

 in young pigs. In some cases it apparently produces immunity which 

 lasts for two or three months. At times, when healthy hogs are treated 

 with serum alone and shortly thereafter exposed to cholera, they seem 

 to acquire a permanent immunity, but this is not always the case, and 

 therefore serum alone can not be depended on to produce a lasting 

 immunity even though the treated pigs be promptly exposed to cholera. 

 It has been stated that serum alone can be used to treat sick hogs. 

 This is true within certain limitations. Ordinarily it is efficacious 

 in the very early stage of the disease, but apparently has only slight 

 effect when the disease has advanced so that a hog shows visible 

 signs of sickness, such as weakness, lack of appetite, and sluggishness. 

 The quantity of serum required for producing immunity or for 

 curing infected animals is influenced by a number of conditions, chief 

 among these being the condition and susceptibility of the pigs and 

 the strength or potency of the serum which is used. No hard and 

 fast rule can be laid down, but as a sort of general guide the doses 

 given below are suggested : 



DOSES FOR SERUM-ALONE INOCULATION 



WEIGHT op HOG 



DOSE OF SERUM 



Below 10 pounds . 

 10 to 15 pounds 

 20 to 30 pounds . 

 40 to 75 pounds 

 100 to 150 pounds 

 175 pounds and over 



10 cubic centimeters. 



15 cubic centimeters. 



20 to 25 cubic centimeters. 



30 cubic centimeters. 



40 to 60 cubic centimeters. 



80 cubic centimeters. 



If the herd is infected the dose of serum should be increased slightly 

 for all apparently well hogs, and all hogs showing high temperatures 

 or other evidence of disease should receive at least a dose and a half 

 of serum. 



In the simultaneous method of inoculation, hog-cholera virus is 

 used in addition to the serum. It has been stated above that the 

 serum alone produces an immunity which lasts for only a very short 

 time. The theory of the simultaneous inoculation is to administer 

 the germs of hog cholera in the virus and at the same time to give 

 a dose of serum which will protect the hogs from cholera. The virus 



