Table 1. Results of UNH Newcastle Spray Vaccine 



Age 4 weeks 5-8 weeks 9-12 weeks 13-16 weeks 



Geometric mean titre ~.7S 6.94 7.11 5.582 



Serum neutralization tests indicated that y^KS i)er cent of the samples 

 neutralized 100 or more neutralizing doses. 



Random samples of l)irds. withdrawn at the same time for challenge, 

 exhibited a resistance of d7 .S per cent, with 98.8 per cent of the susceptible 

 controls dying. 



Spraying of Commercial Newcastle Vaccine 



During a period covering approximately 3 months, experiments were 

 undertaken using the Binks power paint spraver in the administration of a 

 commercially dehydrated Newcastle vaccine. 



Approximately 45.750 birds were sprayed at 2 to 3 days of age with 

 this equipment. The mortality from all causes for 2 weeks following vac- 

 cination was 1.7 per cent. The fluration of the respiratory symptoms was an 

 average of 9 days. 



Blood samples, taken at random, were withdrawn at 4. 8. and 12 weeks, 

 respectively. The geometric mean titres are recorded below. 



Table 2. Results of Spraying a Commercial Newcastle Vaccine 



Age 4 weeks 8 weeks 12 weeks 



Geometric mean titre 5.821 5.743 5.133 



Unfortunately, due to the lack of adequate space for challenge, this 

 process was omitted. 



Serum neutralization tests showed that 80.9 per cent of the samples 

 tested neutralized 100 or more neutralizing doses. 



Spraying of Combination Newcastle- 

 Infectious Bronchitis Vaccine (UNH) 



Field trials were carried out utilizing the Bi strain of Newcastle virus 

 in combination with the strain of infectious bronchitis previously described. 



The first spray vaccination utilizing the combination of Newcastle and 

 I)ronchitis vaccines took place on a farm where 100.000 broilers are raised 

 every 12 weeks, and 50.000 breeders are kept each year. Newcastle disease 

 was a very serious problem on this farm, for it had experienced outbreaks 

 of 31 per cent and 85 per cent losses in the past. Infectious bronchitis and 

 chronic respiratory diseases were also a definite problem. 



Blood samples, taken at random on 2- or 3-day-old chicks, showed a 

 significant H.I. titre in 88.7 per cent of the samples. 



The inoculations took place on either the second or third day of age. 

 Respiratory symptoms were observed on the second day post inoculation 

 and lasted approximately 16.5 days. 



Random samples taken at intervals of 4 weeks presented the following 



geometric mean titres. 



11 



