58 MASS. EXPERIMENT STATION BULLETIN 398 



spread. Pullorum disease Is rarelj' encountered in chicks where owners have 

 adopted effective measures for the eradication and prevention of this disease. 

 Twelve new foci of fowl cholera infection were identified during the year. Fowl 

 cholera has been found on 53 premises during the past 10 years. This disease 

 continues to become more widespread and of greater economic importance. 

 Listerellosis was identified in one chicken, but apparently was not a source of 

 great trouble in the flock in which it was encountered. The 69 tumors encoun- 

 tered were classified on the basis of gross examination as lymphocytoma 35, 

 embryonal nephroma 9, myelocytoma 7, fibrosarcoma 5, hemangioma 4, fibroma 

 2, not identified 2, hematonia 1, leiomyoma 1, and myxoma I. 



The 190 turkej's were received in 48 consignments. The diseases encountered 

 most frequently were coccidiosis, paratyphoid, ulcerative enteritis, and entero- 

 hepatitis. Four cases of pullorum disease were poults shipped in from outside 

 of the State. Swine erysipelas was detected in September in two flocks which 

 were being reared in confinement. Limited observations suggest that this in- 

 fection is apt to be encountered earlier in the season in birds reared in confine- 

 ment than in birds reared on range; also that such an outbreak may be controlled 

 by lettmg the birds out on range. This reduces direct contact between birds and 

 stops much of the feather picking. 



3. Flock Mortality Studies. Morbid and dead birds from the flock main- 

 tained at the College for genetic studies have been examined to determine the 

 causes of mortality and to furnish information for experiments in genetics. This 

 is a continuation of work similar to that conducted in former years. ^ During the 

 fiscal year, 340 birds were examined. Since these represent birds hatched over a 

 period of five years, major emphasis is placed on the group which finished its 

 first la^'ing \ear during the past fiscal year. From the birds hatched in the spring 

 of 1941 , a total of 331 , representing 242 females and 89 males, have been examined. 

 No extensive outbreak of any particular disease w^as noted during the year, but 

 the recognition of 13 cases of aspergillosis was unusual. Fowl paralysis was 

 noted in an increased number of birds, despite efforts to effect a reduction through 

 elimination of families showing a high incidence of the disease. Over three- 

 fourths of the cases of fowl paralysis noted were in birds which had not reached 

 sexual maturity. Fowl paralysis was noted more frequently than any other 

 disease. Other conditions noted in order of frequenc\' were kidney disorders, 

 tumors, reproductive disorders, and cannibalism. Pathological conditions in 

 birds more than 18 months of age were quite similar to those in the jounger birds, 

 except that the percentages of leiomyoma and carcinoma increased markedly. 



4. Salmonella Types Isolated. Paratyphoid organisms isolated from diseased 

 specimens were identified as to t>pe. A total of 15 strains was recovered from 

 consignments received from 10 different flocks. Twelve strains were S. typhi- 

 murium, two w^ere 5. newport, and one was 5. derby. The 5. typhi-murium strains 

 w-ere isolated from two pigeons and ten turkeys (five poults and five mature birds). 

 The 5. newport and 5. derby strains were recovered from poults. In one instance 

 5. typhi-muriii7n and 5. derby were isolated from the same flock, but the stock 

 originated from two different sources which may account for the presence of the 

 two types. 



We are greatly indebted to Dr. Philip Edwards, Department of Animal Path- 

 ology, University of Kentucky, Lexington, Kentucky, who identified these strains 

 as to type. 



5. Avian Encephalomyelitis. Duirng the past year studies of avian encephalo- 

 myelitis were continued. Serial passage of this virus in young chicks has reached 

 the 128th transfer. No perceptible change in the nature of the virus has been 



