IS IT TRUE THAT THE USE OF THE COCCIDIOSIS VACCINE CAN RESTORE THE SENSITIVITY OF TRADITIONAL INFEED COCCIDIOSTATS?
A. Yes. In fact, when used over time, the live oocyst vaccine actually helps to convert resistant field strains to strains that are more susceptible to traditional in-feed coccidiostats. The ability of the vaccine to restore the effectiveness of in-feed coccidiostats was demonstrated in studies conducted at the USDA. Oocysts were isolated from litter samples in houses with broilers that had been vaccinated for five flocks with Coccivac-B. Oocysts also were collected from litter in houses with non-vaccinated birds treated with ionophore coccidiostats. Next, one group of specificpathogen- free (SPF) birds was challenged with oocysts from the vaccinated houses and another group of SPF birds was challenged with oocysts from the ionophore-treated houses. During the challenge, all birds received 60 ppm of salinomycin in the feed. Comparison of the two groups revealed that isolates from the vaccinated houses were fully sensitive to salinomycin, while isolates from non-vaccinated houses varied
