Mycoplasma iowae: field and laboratory studies to evaluate egg transmission in turkeys

In order to study the egg transmission of Mycoplasma iowae in turkeys, two experiments are undertaken. Experiment 1 was a field trial designed to investigate egg transmission in naturally infected turkeys: commercial hens were inseminated with semen from naturally infected toms. Mycoplasma iowae was regularly cultured from dead-in-shell embryos, pips and culls but not from healthy poults. Egg transmission occurred from the second up to the tenth week of production. Experiment 2 was a laboratory study conducted to observe persistence and egg transmission of M. iowae in experimentally infected turkeys. Specific pathogen free (SPF) hens were inoculated either intracheally or intravaginally. They were then artificially inseminated with semen from SPF toms. Very little egg transmission was observed. The cultures from tracheal or vaginal swabs of the inoculated hens showed a limited invasive ability of M. iowae in the adult bird. The humoral immune response as detected by the metabolism inhibition test, was very poor. The observations made in these two experiments show the importance of venereal spread of M. iowae, especially under artificial insemination. Consequently, the need for monitoring toms is obvious.