The number of positive flocks, 25, was two less than in 1944-45. The number 

 of tested birds, 40,011, in positive flocks was also less than the previous season. 

 Approximately 3.6 percent of the birds tested are in positive flocks. It is hoped 

 that the downward trend in the number of positive flocks will continue. Owners 

 of infected flocks are advised not to breed from such flocks until all of the in- 

 fection has been eliminated from the premises either through intensive retesting 

 or by flock replacement with puUoruhi-free stock. 



It should be noted that 70 of the flocks tested in 1944-45 (approximately 15 

 percent) were not tested in 1945-46. Annual testing of all birds on the premises 

 should be observed by every flock owner who operates a breeding flock. 



It is of interest to compare the results presented above with those of the pre- 

 vious season, as listed in the following summary: 



Change 



Classification of flocks 



Tested for the first time: 



Flocks 



Birds 



Percent positive* 



Negative flocks 



Birds in negative flocks 



Positive flocks 



Birds in positive flocks 



Tested intermittently: 



Flocks 



Birds 



Percent positive* 



Negative flocks 



Birds in negative flocks 



Positive flocks 



Birds in positive flocks 



Tested for two consecutive years: 



Flocks 



Birds 



Percent positive* 



Negative flocks 



Birds in negative flocks 



Positive flocks 



Birds in positive flocks 



Tested for three or more consecutive years 



Flocks 



Birds 



Percent positive* 



Negative flocks 



Birds in negative flocks 



Positive flocks 



Birds in positive flocks 



*Based on number of tests. 



Increase Decrease 



25 

 39,595 



28 

 40.407 



7 

 50,795 



61,541 



50.691 



1 

 50.117 



574 



47 



148.175 



0.03 



46 



141.110 



1 



7.065 



0.08 



3 



812 



0.03 



APPEARANCE OF INFECTION IN FLOCKS PREVIOUSLY NEGATIVE 



In Table 3 are listed the testing results of flocks which had been non-reacting 

 for one or more years but showed infection in 1945-46. Twenty "breaks" were 

 detected, which is one less than occurred the previous year. Fourteen flocks 

 had less than 0.5 percent reactors on the first test; two flocks (5 and 10) had more 

 than 1 percent reactors; and the remaining four flocks had between 0.5 and 1 

 percent reactors. Nine flocks had five reactors or less on the original test of the 

 flock. 



