Excerpt:

To determine whether and which spirochetes are cleared from
Ixodes ricinus ticks while feeding on ruminants, ticks were
removed from goats and cattle grazing on tick-infested pastures.
Al-though about a quarter of ticks questing on the pasture was
infected by spirochetes, no molted ticks that had previously
engorged to repletion on ruminants harbored Lyme disease
spirochetes. Ixodes ricinus ticks, however, appear not
to be eliminated. Thus, the more subadult ticks are diverted from
reservoir competent hosts to zooprophylactic ruminants, the
smaller the risk of infection by Lyme disease spirochetes.