Eradication of live F strain mycoplasma gallisepticum vaccine using live ts-11 on a multiage commercial layer farm.

Subsequent to use of a live Mycoplasma gallisepticum (MG) vaccination program, the F strain of MG had been circulating on a commercial layer farm since 1981. In 1994, the ts-11 strain was introduced on the farm; each new placement flock was vaccinated by eyedrop with ts-11 for one production cycle, and then all subsequent placement flocks were left unvaccinated. Birds were monitored by culture and serology before and after vaccination. MG isolates were characterized by random amplified polymorphic DNA (RAPD). MG was isolated from ts-11-vaccinated flocks up to 100 wk of age; all such isolates tested by RAPD were ts-11 type. After ts-11 vaccination was discontinued, no MG was detected in nonvaccinated birds. After the last vaccinated flock was marketed, no MG was detected on the farm. These results indicate a potential use for ts-11 in an MG eradication program.