Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2009
Publication Date: 3/1/2010
Citation: Leigh, S.A., Branton, S.L., Evans, J.D., Collier, S.D., Peebles, E.D. 2010. Effects of vaccination with F-strain Mycoplasma gallisepticum on egg production and quality parameters of commercial layer hens previously vaccinated with 6/85-strain Mycoplasma gallisepticum. Poultry Science. 89(3):501-504. Interpretive Summary: Mycoplasma gallisepticum infection of poultry can lead to significant economic loses for poultry producers. Although vaccines are available, the results of vaccination can range from minimal effects on poultry and minimal protection to maximal protection but potential virulence for some poultry species. This research demonstrated that F strain M. gallisepticum could be safely used to revaccinate layer hens previously vaccinated with the milder 6/85 strain of M. gallisepticum. This combination reduced the undesirable effects of F strain vaccination on hens in post-peak production seen when they are vaccinated solely with the F strain and provides a mechanism for treating birds for which the 6/85 strain is insufficient to contain an M. gallisepticum field strain infection.
Technical Abstract: An experiment was conducted to determine the effect of overlaying (revaccinating) F strain Mycoplasma gallisepticum (MG) at 22 or 45 weeks of age on commercial leghorn hens previously vaccinated with 6/85 strain MG at 10 weeks of age. The treatment groups include unvaccinated hens (group 1), hens receiving 6/85 MG only (group 2), and hens receiving 6/85 MG followed by F strain MG at either 22 (group 3) or 45 (group 4) weeks. There was no effect on egg production or egg size distribution between any of the treatment groups, unlike previous studies looking at F strain vaccination only. Egg quality parameters, including egg shell strength, Haugh unit score, and blood/meat spot were the same between the different treatment groups. There was a difference in the rate of pimpling at post-peak production for the treatment group receiving F strain at 22 weeks, consistent with previously published results. This work suggests that hens previously vaccinated with 6/85 strain MG can be safely revaccinated with F strain MG to increase protection from field strains while ameliorating the adverse effects associated with F strain MG vaccination in layers post onset of lay.