Author
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Miller, Patti |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 4/6/2010 Publication Date: 4/28/2010 Citation: Miller, P.J. 2010. Egg production after virulent challenge is differentially affected by the genotype of Newcastle disease virus (NDV) vaccine [abstract]. Investigacion Aplicada, Salud Animal's 10th Scientific Forum, April 28-May 1, 2010, Oaxaca, Mexico. CD-ROM. Paper No. 4. Interpretive Summary: Technical Abstract: Poultry producers have reported that despite high antibody levels to Newcastle disease virus (NDV), a small decrease in egg production is observed when vaccinated birds are exposed to virulent NDV. While the decrease may be as low as 10%, when this is extended to millions of birds this economic loss is significant. Twenty-two week old commercial layers previously vaccinated four times with live B1 vaccines were used as non-challenged or challenged controls. Two additional groups of these B1 vaccinated birds were boosted with either an inactivated LaSota vaccine or an inactivated vaccine made from the CA/2002 strain that caused the most recent outbreak in the U.S. Pre-challenge antibody levels of the control groups were much lower than that of the boosted birds. The antibody levels of the boosted birds were similar to each other regardless of the genotype of NDV used to formulate the inactivated vaccines. As expected, the control birds that were challenged exhibited a large decrease in egg production, with the production of misshaped eggs 4.5 weeks after challenge. The LaSota boosted birds had a slight decrease in egg production compared to the CA/2002 boosted birds suggesting that antibody type (specificity) may be important to prevent this egg decrease. Similarly, microscopic lesions were found in the control-challenged group but not in either of the boosted vaccine groups. |
