|Peebles, E - MISS. STATE UNIVERSITY|
|Vance, A - FORMER USDA EMPLOYEE|
|Gerard, P - CLEMSON UNIVERSITY|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2009
Publication Date: May 1, 2009
Citation: Peebles, E.D., Vance, A.M., Branton, S.L., Collier, S.D., Gerard, P.D. 2009. Effects of Time-Specific F-strain Mycoplasma gallisepticum Inoculation Overlays on Prelay ts-11-strain M. gallisepticum Vaccination on Blood Characteristics of Commercial Laying Hens. Poultry Science 88(5):911-916. Interpretive Summary: There are currently three live Mycoplasma gallisepticum (MG) vaccines for use in commercial laying chickens. One, the F strain MG (FMG) vaccine is predominantly used by the industry and decreases onset of lay; however, the ts-11 MG and the 6/85 MG vaccine strains while apathogenic and therefore safer, do not displace field strains or wild stains of MG. The objective of this study was to determine the effects of pre-lay ts-11 MG vaccination in conjunction with specific FMG inoculation overlays on the blood characteristics of commercial laying hens. Results of the study suggest that ts-11 MG vaccination in conjunction with time-specific FMG vaccination overlays may be used without any consequential effects on hematocrit or the lipid and protein levels in the blood of commercial layers and further, that the two vaccines used in combination my provide adequate against field strain MG infections while being non-deleterious to layer performance.
Technical Abstract: Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in combination with subsequent time specific F-strain M. gallisepticum (FMG) inoculations on the blood characteristics of commercial laying hens. The following 4 treatments were utilized: 1) sham vaccination at 10 wk of age, 2) vaccination of ts-11MG at 10 wk, 3) ts-11MG at 10 wk overlaid by FMG inoculation at 22 wk, and 4) ts-11MG at 10 wk overlaid by FMG at 45 wk. Parameters measured in both trials were whole blood hematocrit, plasma protein, and serum cholesterol, triglycerides, and calcium. No significant age by treatment interactions and no significant age or treatment main effects were observed for any of the blood parameters investigated, except for serum calcium. At wk 22, serum calcium concentrations were increased by vaccination with ts-11MG at 10 wk, and levels were further increased when the ts-11MG vaccination at 10 wk was overlaid by an FMG inoculation at 22 wk. These results suggest that ts-11MG vaccination at 10 wk of age alone or combined with F-strain inoculum overlays at either 22 or 45 wk may be used without any consequential effects on hematocrit or the lipid and protein levels in the blood of commercial layers. Because elevations in serum calcium were not associated with changes in hen performance, as reported in a previous companion article, it is further suggested that prelay ts-11MG vaccination before FMG inoculation overlays during lay may provide adequate protection against field strain MG infections while being innocuous to layer performance.