Mycoplasma gallisepticum vaccination-challenge: an egg-production model. |
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Authors: | R D Evans Y S Hafez F W Orthel |
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Institution: | Department of Human Ecology, School of Agricultural Sciences, University of Maryland Eastern Shore, Princess Anne 21853. |
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Abstract: | Specific-pathogen-free layer hens in maximum lay were exposed by aerosol to a broth culture of Mycoplasma gallisepticum R' strain. Egg-production loss of greater than 50% was evident 7-14 days following challenge of unvaccinated chickens, with a gradual recovery during the next several days. Various vaccine preparations were tested to determine the effect in the model. All vaccinated chickens exhibited significantly (P < or = 0.05) lower egg-production loss than the unvaccinated controls. The model provides a method for testing treatment effects on egg-production losses resulting from controlled exposure to M. gallisepticum and may be useful in simulating field exposure. |
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