74 MASS. EXPERIMENT STATION BULLETIN 449 



were observed in the previous four years and five cases were observed in the 

 spring of 1948. Affected birds were two to 18 weeks of age (average 11 weeks). 

 The percentage of birds affected averaged about 12 percent. The birds keep the 

 eyelids closed, sometimes manifesting marked irritation by rubbing the eyes on 

 their wings. There is slight lacrimation with marked congestion and moderate 

 edema of the conjunctiva. Ulceration of the cornea varies from small areas on 

 the posterior surface to almost complete involvement. Affected birds sit quietly 

 for one to two weeks, eating and drinking very little, with resultant rapid loss in 

 w^eight. Improvement is gradual thereafter, requiring one to three months, and, 

 in some birds, there remains some cloudiness of the cornea. The cause of the 

 condition has not been established. 



Pox was observed in two canary flocks with a resultant mortality of approxi- 

 mately 35 and 65 percent respectively. Available information indicates that 

 only vaccine of canary origin is of value in immunizing canaries. Vaccine sup- 

 plied by Dr. F. R. Beaudette of the New Jersey Agricultural Experiment Station 

 was introduced into each of these flocks at a time when entirely favorable results 

 could not be expected. The vaccination apparently influenced the course of the 

 disease favorably in one flock and was used too late in the other flock. 



The 393 turkeys were received in 77 consignments, representing about 40 per- 

 cent less material than was received in each of the previous two years. Para- 

 typhoid infection, enterohepatitis, and coccidiosis were the conditions encoun- 

 tered most frequently. Erysipelas, which was quite prevalent the previous year, 

 was identified in only one case. Newcastle disease was identified in two out- 

 breaks. The mortality in poults, apparently infected when received, was about 

 40 percent over a four weeks' period. In an afTected breeding flock, which mani- 

 fested only mild respiratory symptoms, the egg production declined approximately 

 50 percent and the egg shell quality was definitely affected. Field evidence indi- 

 cated that the poults hatched were not affected. 



4. Flock Mortality Studies. No significant new information was obtained in 

 this continuation of examinations on the flock maintained at the University 

 for genetic studies. The number of birds examined was much smaller than in 

 previous years, reflecting in part lower mortality in the flock. Up to January 1, 

 1948, necropsies were made on 117 birds (92 females and 25 males) from the flock 

 hatched in the spring of 1946. Pasteurella avicida was recovered from lesions of 

 the feet of one male. The last previous isolation of this organism in the flock 

 was in 1939 and it was not causing serious trouble at that time. No unusual 

 disease outbreaks were noted. Reproductive disorders, cannibalism, tumors, 

 and kidney disorders were the principal causes of mortality. Gross examination 

 revealed lymphocytoma in only one female and one male, fowl paralysis in three 

 females and one male, and myelocytoma in four females. 



5. Infectious Bronchitis Control. During 1947 a total of 263 flocks was en- 

 rolled in the infectious bronchitis control program, an increase of 46 flocks over 

 the previous season. The results continue to be satisfactory and more flock 

 owners are beginning to realize the value of a flock immune to bronchitis. During 

 the past year 177 flocks were tested for immunity to infectious bronchitis, 133 

 of which were found to be immune, 27 susceptible, and 17 questionable. 



The poultry bronchitis laboratory also tested flocks for Newcastle disease. 

 A total of 300 flocks was tested, 115 of which were found positive and 185 nega- 

 tive. 



Thirty-six flocks were found to be positive for both Newcastle disease and 

 infectious bronchitis. Newcastle disease was identified in all but one county 



