Progesterone release and incidence of bacteria following disinfection and reuse of controlled internal drug release devices (CIDRs)
Controlled internal drug release (CIDR) devices have been reused in cattle estrous synchronization protocols. However, the effectiveness of the CIDR and incidence of vaginal bacteria secondary to reuse remains unclear. Therefore, 2 experiments were conducted to evaluate plasma progesterone and vaginal bacteria utilizing used CIDRs disinfected prior to reuse. In Exp. 1, cows received a new CIDR (CONT) or a used CIDR disinfected by 1 of 3 methods: autoclaved (AUTO), dishwasher (DISH), or chlorhexidine (CHLO). No difference was detected in plasma progesterone (P = 0.24) concentration between treatment groups. Daily progesterone concentrations differed during CIDR treatment (P < 0.001) on d 0, 3, and 7. In Exp. 2, vaginal mucous samples were collected pre- and post-synchronization. Cows received CONT, AUTO, or CHLO treated CIDRs. Bacterial loads in vaginal mucus cultured on TSA blood agar did not differ by treatment (P = 0.29) nor by day (P = 0.69). CHLO-treated CIDRs had higher bacterial gram-negative colony counts than those disinfected with AUTO or CONT (P = 0.0035), and bacterial load was higher on d 7 than d 0 (P = 0.0025) for vaginal mucous samples cultured on EMB agar. Based on the results of these studies, twice-used treated CIDRs do not reduce progesterone plasma concentrations, however, risk of bacterial contamination of the vagina must be considered.