281. MASS. EXPERIMENT STATION BULLETIN 271 



DEPARTMENT OF VETERINARY SCIENCE 

 J. B. Lentz in Charge 



Poultry Disease Elimination Law. (H. \nn Roekel, K. L. Bulli.s, G. L. 

 Dunlap, and O. S. Flint). The progre.ss made in puUorum disease eradica- 

 tion during the 1929-1930 season is reported in Control Series Bulletin 

 No. 53. Approximately one-seventh of the poultry population of Mass- 

 achusetts was tested and the volume of work is steadily increasing. Com- 

 pared with the previous season the following increases are noted: — 48 

 tested flocks, 76,802 tested birds, 82,590 tests, 81 negative flocks, and 53 

 non-reacting 100 per cent tested flocks. Further comparison shows that 

 tho average percentage of infection was reduced from 4.25 to 2.35 per 

 cent. 



A study of 60 flocks tested for two consecutive years showed that in- 

 tensive retesting or short-interval testing was more effective in eradicating 

 the disease than annual testing. Similar results were obtained in 30 fTocks 

 tested for three consecutive years. 



The relation of sexual maturity to pulloruni disease eradication was 

 studied in ten flocks which were subjected to the intensive testing plan. 

 The results show tliat sexual maturity of i)ullets does not appear to play 

 a role in eradicating the disease. From an eradication point of view, 

 early pullet testing in infected flocks is more desirable tlian testing more 

 mature birds. 



Failure in eradicating the disease or in maintaining a pullorum disease 

 free flock was in most instances due to a lack of observing sound eradica- 

 tion measures. More eifective results would be obtained if all poultrymen 

 would follow the laboratory suggestions more closely. 



Two liundred and twenty-eight reacting birds were sul)mitted to the 

 laboratory for necropsy. The necropsy findings often aided in estab- 

 lishing the true status of a flock. No reactors were detected among the 

 584 tested fowl other than chickens. 



This laboratory again participated in the annual pullorum conference 

 of the Eastern States' laboratory workers. The ])urpose of this con- 

 ference is to standardize and adopt uniform, sound methods which will 

 prove practical and effective in pulloruni disease eradication. 



Among the blood samples submitted since August 1, 21.123 samples, 

 representing 37 flocks, were tested with Brucella ahurfus antigen in 1-25 

 and 1-50 dilutions. All samples were considered negative. 



An effort was made to determine the length of time >'. pullorum will 

 remain viable under various conditions. It was observed that the organism 

 can remain viable on a dry piece of cloth in a Kolle flask for fourteen 

 weeks and possibly longer. 



The problem of "jelled serum" samples is being investigated. Results 

 thus far show that the number of jelled samples may be greatly reduced 

 if the freshly drawn blood is not subjected to low temperatures. 



Laboratory Service — Pathology. (G. L. Dunlap). This service was 

 used by 352 people, 71 making personal calls to deliver specimens or 

 discuss poultry diseases. Ten hundred and seventy-nine specimens were 

 examined, of which 1016 were poultr\', the remainder consisting of other 



