Differences in pain and trauma caused by common sampling devices used in the United States for Tritrichomonas foetus testing in bulls.

Abstract

Objective: The aim of the study was to evaluate the efficacy, pain response, and potential epithelial trauma of 3 devices (an equine infusion/insemination pipette, the Pizzle Stick, and the Trichit) used for sampling bulls naturally infected with Tritrichomonas foetus in the US.

Methods: The study occurred between March 2023 and May 2024. Twelve bulls naturally infected with T foetus were sampled with the use of a Latin square design. Three devices were used to collect preputial samples, analyzed via reverse-transcription quantitative real-time PCR for diagnostic accuracy. Pain responses were scored by 2 veterinarians. The penis and prepuce of each bull were examined for epithelial trauma 24 hours after sampling. Histologic evaluation of biopsy samples from the penis and prepuce of 8 bulls was conducted after euthanasia to assess cellular damage.

Results: All devices provided comparable diagnostic accuracy. Pain scores differed significantly, with the Pizzle Stick causing the least pain and the Trichit causing the most. Epithelial trauma did not show statistical differences between devices, though some trauma was noted, particularly with the equine insemination pipette. Histologic analysis revealed epithelial hyperplasia of the penis and prepuce, unrelated to any device.

Conclusions: While all devices effectively diagnosed T foetus, the Pizzle Stick demonstrated the most favorable pain scores, making it the recommended option for reducing discomfort and minimizing risk to both animals and veterinarians.

Clinical relevance: Veterinarians have multiple diagnostic sampling methods for T foetus. The Pizzle Stick's lower pain score makes it the best choice, balancing animal welfare and diagnostic efficacy.