CUTANEOUS VACCINE FOR FOWL POX 



247 



Table 2. — Total and Daily Gain in Weight During the Stage of Infection 

 Following Cutaneous Vaccination. (Summarized from Table 1.) 



EXPERIMENT 1— White Leghorn Cockerels— age 210 days 



Treatment 



Controls 



Vaccinated (200 mgm.) 



Length 



of 

 stage, 

 days 



EXPERIMENT 2— R. I. R. Pullets and Cockerels— age 80 days 



EXPERIMENT 3— R. I. R. Pullets and Cockerels— age 68 days 



Interpretation. — In forming conclusions from these data it is necessary to 

 bear in mind that individual birds vary considerably in tendencies governing 

 increase in weight. This is influenced by several factors; chiefly, by the rela^ 

 tive amiount and the quality of the feed consumed by the individual. The 

 variation iri initial weight is another factor which must be considered wheq 

 interpreting these figures. This influenced the average gain in weight of a 

 group, as a whole, to some extent even though each group was carefully 

 selected as to comparable weight. 



In general these data indicate that the vaccine does not cause a retarda- 

 tion in the gain in weight following its administration to birds 80 days of 

 age or older. They do indicate, however, that there is a slight retardation in 

 gain in weight following its administration to birds 68 days of age. This 

 .slight retardation in gain in weight was relatively unimportant for the same 

 reasons mentioned in connection with the slight retardation in early egg 

 production. Recovery was rapid. 



The 100 mgm- vaccine produced a follicular reaction comparable to that 

 of the other vaccines and, therefore, its use appears to be indicated on birds 

 of an age comparable to those in experiments 2 and 3. It contains one-half 

 as niucli virus as the standard vaccine, which offsets to some degree the 

 danger of spreading the infection and contaminating the premises. 



