Comparison of Ear Tipping Techniques to Identify Sterilized Community Cats: A Randomized Controlled Trial

Introduction: Many methods are used for ear tipping, but the majority of practitioners have experience with only one. This study sought the most effective method of ear tipping, with the primary outcome being breakthrough bleeding, and secondary outcomes being immediate bleeding, duration, conformation to target length, cosmesis, client satisfaction, and tipper preference. Methods: This randomized controlled trial, conducted between June 2022 and February 2023, enrolled cats at least 6 months old presented for Trap-Neuter-Return to one of seven techniques. Techniques were combinations of cutting tools, including Mayo scissors (MS), wood burning tool (WBT), and scalpel blade (SB), and hemostatic agents, including styptic gel (gel) and compounded hemostatic paste (CHP), and hemostat (H). Removal of 1 cm of the left ear pinna was timed, and breakthrough bleeding, the primary outcome measure, was blindly assessed. Client satisfaction was captured at discharge, 1 day, and 1 month, and cosmesis determined by three blinded independent raters. Results: There were 252 cats from 80 unique colonies, with 36 per group, across 8 clinic days. The overall rate of breakthrough bleeding was 7% (95% confidence interval [CI]: 4–11%) and differed by technique (P < 0.0001). Neither WBT+H nor MS+H had any occurrences (95% CI: 0–10%), while SB+H/gel had the most (29%, 95% CI: 15–48%). The median time was 10 s (interquartile range [IQR] 7, 13). Tips were greater than target with WBT+H (33%, odds ratio [OR]: 3.8, P < 0.0001) as compared to SB+H. While SB+H had the highest mean cosmesis score (5.12/6, standard deviation [SD]: 0.87), WBT+H (4.4/6, SD 1.07) scored significantly lower (P = 0.002). Clients were satisfied with 88% (95% CI: 83–92%) of the ear tips at discharge (although response rate was insufficient for 24-hour and 1-month post), and there were no associations with technique. All 4 tippers preferred SB+H/CHP. Conclusion: No technique was superior in all measures. While WBT+H and MS+H were superior by the primary outcome, SB+H/CHP was unanimously preferred by tippers.