首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Immunization of broiler chickens with a commercial infectious laryngotracheitis vaccine in the drinking water.
Authors:L B Hayles  W C Newby  H Gasperdone  and E W Gilchrist
Abstract:Seventy-five thousand broiler chickens in four flocks were immunized at four weeks of age with a commercial infectious laryngotracheitis vaccine administered in the drinking water. Three of the flocks exhibited a vaccine reaction represented by mild respiratory illness between seven and 14 days after vaccination. Immunity challenge experiments demonstrated 97% protection in one trial and 67% in another trial in which the dose of challenge virus was increased fourfold. In the latter trial a parallel comparative vaccination by eye administration was 87% protective. None of the vaccinated birds died of the challenge exposure whereas all the unvaccinated control chickens became ill, several showed the acute severe form of the disease and 36% died. Similar favourable results were obtained in large-scale water immunization programs involving more than 200,000 birds. Serum antibody levels determined before immunity challenge were, within wide limits, inversely related to the severity of clinical disease which developed from the challenge inoculation.
Keywords:
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号