Efficacy of Graded Levels of p-Ureidobenzenearsonic Acid Against Different Levels of Exposure to Histomoniasis in Turkeys 5 and 13 Weeks Old ,

Abstract

WELTER and Clark (1961) reported that p-ureidobenzenearsonic acid (p-UBAA), administered continuously starting one week before infection, reduced mortality and lesions due to histomoniasis. Similar results were obtained in challenge experiments by Sullivan et al. (1964, 1965), when dietary treatments were initiated five days prior to exposure. Lund (1955) studied histomoniasis mortality as related to the size of the infective dose. He observed a decrease in mortality as the infective dose was decreased.The purpose of this study was to determine the efficacy of graded levels of p-UBAA against different levels of exposure to histomoniasis in turkeys five and 13 weeks of age.EXPERIMENTAL PROCEDURETwo challenge experiments were conducted in which turkeys were artificially exposed to embryonated Heterakis gallinae ova containing Histomonas meleagridis. Exposure was accomplished by placing the H. gallinae ova directly into the crop by means of a pipette. The post-challenge periods were 28 and 27 days for .