Efficacy of a medicated feed to treat parasites of wild Northern bobwhite quail (Colinus virginianus)

Parasites are ubiquitous in wildlife populations and can cause reduced fecundity and survival in several species, as well as influence cyclic population fluctuations. Anthelmintic treatment has been found to mitigate these negative effects of parasites in many wild populations. It is suspected that the eyeworm Oxyspirura petrowi and caecal worm Aulonocephalus pennula are negatively affecting northern bobwhite quail (Colinus virginianus) populations in semiarid ecoregions of Texas. However, it is difficult to determine the effect of parasites on a population without experimentally reducing the parasite. The purpose of this study was to test the efficacy of an anthelmintic medicated feed at reducing parasite burden in wild bobwhite as part of a series of studies for United States Food and Drug Administration (USFDA) registration. Two pilot studies found that the medicated feed had a 71.5% and 81.7% efficacy against caecal worms and eyeworms, respectively, and significantly reduce total parasite burdens (p < .05). For the final efficacy study, control or medicated feed was randomly assigned to 12 feeding systems on a private ranch and administered for 21 consecutive days to determine the efficacy of anthelmintic treatment of eyeworms and caecal worms in bobwhite. Up to five bobwhite were collected and assessed for parasite abundance from each feeding system following the 21-day treatment to assess efficacy. There was a significant difference for caecal worms between treated and control bobwhite (p < .0001), with a 99.5% efficacy. This demonstrates that the medicated feed is a viable method for reducing parasites in wild bobwhite and could be used to elucidate the impacts of parasites on bobwhite populations.