Abstract

Injectable anesthetic drugs are frequently used on pinniped species to facilitate handling for health assessments, sample collection, instrumentation and disentanglement.¹ Remote field environments are not always conducive to inhalant anesthesia, necessitating the use of safe, effective, and reversible injectable anesthetic protocols. Tiletamine/zolazepam has been used frequently in adult gray seals but has not been reported for use in pups.^2,3,4,5 Additionally, alfaxalone and medetomidine-midazolam has been utilized in adult gray seals.^6,7 Butorphanol-midazolam has been used safely in many species of phocids, though this drug combination has not been reported for use in gray seals.^1,8 A combination of butorphanol-midazolam, midazolam alone or tiletamine/zolazepam was used to sedate 26 gray seal mom-pup pairs to facilitate collection of serial samples in a field environment. An additional 25 weaned pups were sedated once for instrumentation only. Moms were handled twice at 3 and 12 days postpartum, pups were handled three times at 3, 12, and 28 days postpartum. Respiratory rate, heart rate, capillary refill time, mucous membrane color and response to tactile stimuli were monitored to assess depth of sedation. A combination of butorphanol-midazolam produced effective and reliable sedation in 3-day and 12-day-old pups and was less effective in weaned pups. Tiletamine/zolazepam produced safe and reliable sedation in short duration weaned pup procedures and in moms. Optimization of safe and effective field sedation minimizes handling stress, expedites sample collection and instrumentation, and ensures safety of researchers and veterinary staff.

Acknowledgments

The authors thank the staff and volunteers associated with the Department of Fisheries and Oceans Canada, Sable Island Grey Seal Mark-Recapture Program for their contributions to grey seal field research.

*Presenting author

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