Efficacy of ipronidazole against trichomoniasis in beef bulls. Preputial smegma samples from 195 beef bulls were collected repeatedly and cultured for Tritrichomonas foetus. Seventy-five (38.5%) of these bulls were positive for trichomonads on at least 1 culture. Sensitivity of the culture procedure (number of positive cultures/number of total cultures from known-positive bulls) was 81.6 %. Storage of preputial smegma in lactated Ringer's solution at 5 C for 24 hours resulted in a 14% loss of sensitivity. Seventy-three of the 75 infected bulls were available for treatment and were alloted randomly to 2 groups. Bulls in both groups were treated with procaine penicillin (7,000 IU/kg, IM) for 2 days before ipronidazole treatment. Thirty grams of ipronidazole powder was dissolved in 60 ml