[hit challenge for Xeuca.stle inuminit) \va> carried mit 1)_\ injecting" 

 .5 CO. of 10 nild's (oljtained by l)ird titre ) of the Honey strain of virus in- 

 tramuscnlarlv. l^iirds showing s\mptoms of paralysis were considered as 

 dead. 



Preliminary Laboratory Results 



'liiiKiv CHICKS, parentalh' immune to Newcastle disease, were u>ed in the 

 first laboratory trial. The chicks were sprayed on the second day. A respir- 

 atory "take" occurred 5 days later which lasted for an additional 5 days. At 

 5 weeks, blood samples were taken for an H. I. and S. X. test, and the en- 

 tire group was challenged with 10 mld's (»f the P)oney challenge strain of 

 Newcastle virus. Two birds died and one showed paralysis. Seventy and 

 one-half (70.5) per cent of these birds showed positive Td. I. tnres while 

 79.3 per cent showed positive neutralization litres. 



Diu'ing this same period laboratory trials were being run on the se- 

 lected strains of infectious bronchitis mentioned previously. .\t this juncture 

 it was decided to combine Newcastle and infectious bronchitis vaccines. The 

 Blacksburg strain of Newcastle \irus and selected strains of infectious bron- 

 chitis were used in these trials. 



Four parallel groups of 30 susce])tible 4- week-old chicks were sprayed 

 with combination Newcastle and infectious bronchitis strains. In addition. 

 2 groui)s of 30 chicks, 3 and 4 days of age. i)arentally imnnnie to Newcastle 

 and infectious bronchitis were sprayed. 



Recording sterility aiul pott'iu-v, 



8 



