9 



Another man had 9.87 per cent infection last year and 44.75 per cent in- 

 fection in the 1927-28 test. He decided to eliminate his infected flock after 

 the 1926-27 test and bought eggs for replacement from flocks known to have 

 no reactors in tlieni for two consecutive years, but made the mistake of hatch- 

 ing the disease-free eggs in an incubator with eggs from diseased flocks. The 

 result was an abnormal mortality among his clucks and a high percentage of 

 reactors in the survivors. 



Two of the 13 flocks, having more than 20 per cent infection and testing 

 for two or more consecutive years, were discovered to contain reactors whicii 

 had been found on a previous test. In answer to a questionnaire, four of 

 these 13 flock owners reported that they had kept reactors for egg-laying- 

 purposes, one reported that he had not, and no answer was received fro)n 

 eight. Nine of this group tested all their birds in 1927-28, while four tested 

 only a portion of their flocks. In 1926-27, six of the group failed to test all 

 their birds. 



An individual study of eacli flock and its management needs to be made in 

 such cases as described to ascertain wiiether or not it is iulvisable to attempt 

 to eradicate bacillary white diarrhea. In most instances after such a study, 

 the flock owner would probably be advised to stop breeding and to buy 

 disease-free stock yearly for replacements. 



For data on the range of infection previous to 1923-24, the reader is re- 

 ferred to Table II of Control Series Bulletin No. 39. 



Progress in Control of Salmonella Pullorum Infection 



It is a diiiicult problem to determine with accuracy the progress being made 

 in the control of the disease in Massachusetts. The work in the past has been 

 partly of an educational nature, leading to the present plans which we be- 

 lieve will show nuich greater results in the future. Poultrymen have not 

 realized the necessity for total flock testing; have thought it unnecessary to 

 test each year after the flock became free from the disease, or if they did 

 test, it was on only a small percentage of the flock; and have kept reactors 

 for egg-producing purposes, and some have not removed reactors from the 

 breeding flocks. All these factors have hindered progress. 



However, as seen by studying Table V, control of the disease is being- 

 accomplished. 



There has been a constant increase in the number of flocks tested each 

 year during the five-year period from 1923-1928. With the exception of 1926- 

 27, the number of non-reacting flocks has steadily increased. In 1926-27 there 

 were 105 flocks tested for the first time, and nearly twice as many birds were 

 tested as in any previous season. There were 108 flocks which were tested 

 in 1925-26, but not in 1926-27. Since 81 of these flocks were on the non- 

 reacting list of 1925-26, only 43 non-reacting flocks of 1925-26 were again tested 

 in 1926-27. The large number of new flocks tested and the lack of consecu- 

 tive 100 per cent testing proliably account for the decrease in number of 

 non-reacting flocks that season. 



A similar condition existed in 1927-28, when 106 new flocks were tested, 

 but 93 of those tested in 1926-27 were not tested in 1927-28. Among these 

 93 there were 35 of the 114 non-reacting flocks of that year. 



The most significant data included in Table V are the comparisons of the 

 tests made with the poultry population of Massachusetts given in the 1925 

 census. There has been a marked increase in the percentage of the total 

 birds in the State which have been tested during the past two years, 6.27 per 



