University of Arkansas, Fayetteville Division of Agriculture


The goal of this research was to determine the extent of resistance that turkey roundworms, Ascaridia dissimilis, have developed to anti-parasitic chemicals used in commercial poultry operations. Roundworm infections in turkeys have resulted in monetary losses for the poultry industry for years, generally due to poor feed conversion. The infection itself is subclinical and many turkeys have a light to moderate worm burden. Since parasitisms are light, this leads to the infections being noticed only during processing. Ascaridia dissimilis infections consist of adult worms and developing larvae with the latter comprising most of the worm burden and causing the most damage. In this study, eggs were collected from A. dissimilis found in turkeys previously treated with various parasiticides and combinations thereof. These eggs were in turn used to instill artificial infections in turkeys on site. These artificially infected turkeys were then treated with fenbendazole or albendazole. A third group of birds was left untreated as a control group. Drug efficacies were determined based on parasite loads post treatment (at necropsy). The results of this study will improve current knowledge of chemical resistance associated with these drugs.