13 



per cent. The percentages of non-reacting flocks in Group III never exceeded 

 those of Group IV. 



The results presented clearly demonstrate that intensive retesting will ex- 

 pedite eradication of the disease and consequently bring to the poultryman 

 the benefits and profits derived from a pullorum disease-free flock. 



Pullet Testing Should Not Be Postponed Until Birds Reach Sexual Maturity 



The age at which a pullet becomes eligible for testing has been questioned. 

 Some investigators are of the opinion that the eligibility is influenced by 

 sexual maturity. This phase in the eradication program has been given rela- 

 tively little attention. From the eradication viewpoint, the infection should 

 be detected and eliminated as early as possible. Therefore, if a flock of pullets 

 is known to be infected, eradication measures should not be postponed until 

 the birds attain sexual maturity or egg production. This pt-ocedure will de- 

 crease the potential amount of infection in the flock and consequently lessen 

 the spread to non-infected birds. Pullet testing can be carried on while 

 pullets are still on range so that only non-reacting birds may be placed in 

 the laying houses. 



During the past season 10 infected flocks followed the 100 per cent intens- 

 ive testing plan. The number of pullets in the flocks varied from 214 to 2896. 

 The average percentages of infection on first test ranged from 0.18 to 28.29 

 per cent. Records of the percentage of pullets that had sexually matured 

 were obtained for each test. Some flocks were tested before the pullets had 

 laid or when they had just commenced to lay, and others were tested when 

 the majority of pullets were well in production. Figure 5 shows the number 

 of tests made on each flock, the percentage of the total reactors detected at 

 each test, and the percentage of sexually mature pullets. Flock A was tested 

 before any pullets were laying, and 68.24 per cent of the total reactors were 

 detected on first test which revealed 28.29 as the average percentage of in- 

 fection. Four tests were required to eliminate the infection from the flock 

 and upon fourth test 78.67 per cent of the pullets had laid. In flocks B and 



C, all the reactors were detected on first test. Flock B revealed 4.21 per 

 cent infection, and 90 per cent of the pullets had laid on first test. Flock C 

 revealed 0.18 per cent infection and 15 per cent of the pullets had attained 

 isexual maturity. In flock E, 93.75 per cent of the total reactors were de- 

 tected on first test when only 14 per cent of the pullets had laid. The aver- 

 age percentage of infection was 2.07. The second test was negative and the 

 third revealed one reactor when 83 per cent of the pullets had laid. In flocks 



D, F, G, H, I, and J, the average percentage of infection was 22.12, 0.97, 

 2.92, 1.86, 2.25, and 8.64 respectively. The number of pullets tested in each 

 of the flocks D, F, G, H, I, and J, was 330, 2896, 855, 2469, 579, and 822 re- 

 spectively. In flock J, the percentage of sexually mature pullets was 55 per 

 cemt on first test and 100 per cent on second test On the third test the in- 

 fection was still present. Similar results were obtained in flock I. There 

 appeajrs to be no correlation between the percentage of total reactors deiteot^ 

 ed and the percentage of pullets that have laid. Further informtation will be 

 gathered from a practical eradication viewpoint to determine at what definite 

 age pullets can be subjected to puMonun disease eradication measures. 



