May, 1937] Agricultural Research in N. H., 1936 31 



The influence of feeding and litter treatment on chronic coccidiosis 

 was also investigated. A pen started with hard grain feeding along with 

 the mash was compared \\ath a pen that was not fed hard grain for the 

 first four weeks; and both pens were compared with others in which the 

 litter was treated and the birds fed according to recommended practice. 

 No coccidiosis developed, but mortality and culling were lower in the 

 litter-treated pens. The pens were kept dry at all times, and the results 

 tend to confirm other observations that there is much less trouble with 

 the disease in diy pens. Half of the birds were placed in batteries, and 

 egg records of these were much lower than for the birds kept in pens. 



Another group of birds was divided into six pens of 20 birds each. In 

 five pens three birds were treated periodically with oocysts of chronic 

 coccidia, receiving otherwise different rations and treatments. Again all 

 pens were kept dry, however, and the disease did not develop. Records 

 of egg production from October to April show considerable variation as 

 follows : 



Control Group, no oocysts 2045 eggs 



Oocyst Groups: Litter treated with sulphur weekly. . . 1879 eggs 



Jo sodium bicarbonate in feed 1742 eggs 



Jo sulphur in feed 1529 eggs 



10% milk sugar in feed 1233 eggs 



Regular feed 1214 eggs 



The work was in charge of C. L. Martin, T. B. Charles, R. C. Durgin 

 and S. R. Shimer. {Purnell Fund) 



Epidemic Tremors of Chickens 



Our studies of epidemic tremors, the trembling chick disease, were 

 reported at the World's Poultry Congress in Berlin, Germany, in Aug- 

 ust, 1936, and a summary has been published in Station Circular 51. 

 The results indicate that the disease is not hereditary ; that it may occur 

 under different types of brooding and feeding systems; that it does not 

 appear to be caused by variations in incubation or hatching tempera- 

 tures; and that affected birds show no significant difference in body tem- 

 peratures or blood counts. Transmission studies have thus far failed 

 to indicate how the disease spreads. The work is handled by C. A. Bot- 

 torff, A. E. Tepper, T. B. Charles and R. C. Durgin. {Purnell Fund) 



Vaccinating for Bang's Disease 



Cattle from the age of two months to four years were vaccinated by 

 C. L. Martin with an attenuated Bang's disease vaccine from both Fed- 

 eral and commercial sources. The purpose was to find out if cattle so 

 vaccinated would later give a negative reaction to the standard tube 

 agglutination test for Bang's disease, and how long after inoculation 

 they would give a positive reaction. 



Tests showed that all animals vaccinated gave a strong postive reac- 

 tion one month after inoculation. Previous to vaccination two blood 

 tests were made to find out the reaction of blood. {Purnell Fund) 



