The production of EAE-free lambs from infected dams using multiple ovulation and embryo transfer

This investigation aimed to ascertain whether embryo transfer was a feasible method of breaking the disease cycle caused by Chlamydia psittaci (ovis). Ten naive ewe lambs were inoculated orally with the T76 and G188 isolates of C. psittaci (ovis) in late pregnancy. Five animals which sero-converted to the complement fixation test (CFT) were used as donors for a multiple ovulation and embryo transfer programme. Three ewes excreted chlamydiae at parturition 1 year after inoculation, with one animal exhibiting a CFT titre indicative of clinical disease. Twelve embryos collected from these three donors and transferred to seven disease-free recipients survived and were not infected, nor were their recipient dams. It therefore appears possible to infect ewe lambs during the final stages of pregnancy with the disease manifesting itself during the following breeding season. Embryos collected from infected animals do not appear to transmit the chlamydia causing enzootic abortion.