Distribution of Tests and Reactors 



Table 1 gives the distribution of tests and reactors by counties and by breeds. 

 In 13 counties, 662,715 chicken samples were tested, of which 1,757 (0.27 percent) 

 were positive. Middlesex, Worcester, and Norfolk counties led in the number 

 of samples tested. In five counties (Barnstable, Dukes, Franklin, Plymouth, 

 and Suffolk), no reactors were found among the birds tested. No reactors have 

 been found in Barnstable and Plymouth counties for three successive years. 

 Norfolk County had the highest percentage (1.67) of positive tests, which is 

 attributed to one large infected fleck. 



The following breeds and varieties were tested: Bantam, Barne\ elder, Barred 

 Plymouth Rock, Black Minorca, Brahma, Brown Leghorn, Cochin, Columbian 

 Reck, New Hampshire, Rhode Island Red, Silver Laced Wyandotte, White 

 American, White Leghorn, White Plymouth Rock, White Wyandotte, and 

 Crosses. Rhode Island Red and Barred Plymouth Rock are the predominating 

 breeds. Reactors were detected among the Barred Plymouth Rock, Brown Leg- 

 horn, New Hampshire, and Rhode Island Red breeds. 



Of the total number of samples tested, 601,932 were obtained from females 

 (hens 67,625 and pullets 534,307) and 60,783 from males. The percentages of 

 reactors were 0.02 among the hens, 0.28 among the pullets, and 0.44 among the 

 males. The greater percentage of reactors among the males may be explained 

 in part by the fact that most of them were detected in one large infected flock. 

 In this large flock, the percentage of reactors among the females was 3 and among 

 the males 5 percent. 



Testing of Fowl Other than Chickens 



A total of 5,109 samples collected from fowl other than chickens was tested for 

 pullorum disease. Six ducks, 2 guinea fowl, and 5,101 turkeys were tested with 

 no reactors. These results indicate that pullorum disease is no serious problem 

 to Massachusetts turkey breeders. It is advisable however, that the owners of 

 turkey breeding flocks exercise every possible precaution to prevent the intro- 

 duction of this disease into their flocks. 



Duri lg the past year, four turkey flocks representing 6,579 samples were tested 

 for paratyphoid infection. Three flocks were classified as non-reacting but re- 

 actors were found in the fourth flock on tests repeated at frequent intervals. 

 As was pointed out in the previous Annual Report, the macroscopic agglutination 

 test is not sufficiently reliable in detecting infected birds so that it can be employed 

 as a practical means of eliminating this infection from commercial flocks. 



Among 15 reacting birds received at the laboratory for necropsy, the causative 

 agent was isolated from 1 1 . 



Annual Testing of Flocks 



Table 2 shows the results from flocks tested for the first time, intermittently, 

 for two consecutive years, and for three or more consecutive years. In every 

 group, the number of birds tested showed an increase over the previous season. 



Flocks tested for the first time numbered 77 and represented 62,435 birds and 

 62,501 tests, with an average of 0.04 percent positive tests. Only three of the 

 flocks tested for the first time were found to be infected. In one flock of 13 birds, 

 4 reactors (30.77 percent) were detected. In the other two flocks, 1,811 and 1,379 

 birds were tested, with 0.83 and 0.51 percent reactors, respectively. Approx- 

 imately 95 percent of all the birds in flocks tested for the first time were in non- 

 reacting flocks. It is indeed encouraging to find so little infection among flocks 



