Effect of Mycoplasma gallisepticum bacterin on egg-transmission and egg production.
Groups of white leghorn hens were vaccinated twice with a Mycoplasma gallisepticum (MG) bacterin, once with bacterin, or left unvaccinated. Four weeks after vaccination, they were challenged with virulent R strain MG. Egg production was significantly higher in challenged vaccinated groups than in the challenged control group. Four challenged control hens went out of production, whereas only one twice-vaccinated hen did. MG was first isolated directly from eggs 5 days postchallenge (PC) in twice-vaccinated hens, 4 days PC in once-vaccinated hens, and 2 days PC in controls, and the hens continued to lay positive eggs till the end of the experiment 7 weeks PC. MG was found in 17.65%, 38.55%, and 45.90% of eggs cultured in twice-vaccinated, once-vaccinated, and control groups, respectively. Nine of 16 twice-vaccinated hens were found to be shedding MG through their eggs, whereas 15 of 17 once-vaccinated hens and 14 of 16 controls were shedding MG through their eggs.
Sasipreeyajan
J
J
College of Veterinary Medicine, University of Minnesota, St. Paul 55108.
Halvorson
D A
DA
Newman
J A
JA
D000818:Animals; D001428:Bacterial Vaccines / Q000494:pharmacology*; D002645:Chickens / Q000502:physiology*; D005260:Female; D009174:Mycoplasma / Q000276:immunology*; D009175:Mycoplasma Infections / Q000503:physiopathology / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary*; D010058:Oviposition; D011201:Poultry Diseases / Q000503:physiopathology* / Q000517:prevention & control / Q000635:transmission; D014611:Vaccination / Q000662:veterinary*
D001428:Bacterial Vaccines