Abstract

There are few anesthetic protocols for American alligators reported in the literature. Study objective was to compare two injectable anesthetic protocols in subadult American alligators (Alligator mississippiensis). Mean±SD body weight and length were 4.75±0.48 kg and 111.52±9.93 cm. Six clinically healthy alligators were anesthetized in a prospective randomized crossover study design. Treatments were: K (ketamine 5 mg/kg, dexmedetomidine 50 µg/kg, and midazolam 1 mg/kg) and A (alfaxalone 5 mg/kg, dexmedetomidine 50 µg/kg, and midazolam 1 mg/kg), both administered intravenously in the lateral occipital sinus. Anesthesia was monitored throughout its duration of 150 min. Time to induction, loss and return of reflexes (righting, withdrawal, palpebral, corneal, and cloacal), ventilation loss, and recovery were recorded. Heart rate and cardiac rhythm, respiratory rate, end-tidal carbon dioxide, esophageal and cloacal temperature were also recorded. There were no statistical differences in heart and respiratory rate, end-tidal carbon dioxide, and esophageal temperature between treatments. Palpebral, cloacal, and righting reflexes were consistently lost in all animals for both treatments. All animals recovered for both treatments. Five alligators from treatment K did not lose spontaneous ventilation (p=0.0156), or front and hind toe pinch withdrawal reflexes (p=0.0313 and 0.0313, respectively). In treatment A, all alligators lost ventilation, clinically significant in one individual, and front and hind toe pinch withdrawal reflexes. Alligators in treatment A were manually ventilated using room air until return of spontaneous ventilation. Consequently, at the doses used and given intravenously, K treatment caused less apnea than treatment A.

Acknowledgments

The authors thank the Louisiana Veterinary Clinical Sciences CORP-grant for the financial support and the Louisiana Department of Wildlife and Fisheries for providing the animals.