EVALUATION OF THIAFENTANIL-MEDETOMIDINE-KETAMINE COMBINATIONS FOR ANESTHESIA WITHOUT THE USE OF A RESTRAINT DEVICE IN ZOO-HOUSED GIRAFFES (GIRAFFA CAMELOPARDALIS).

Abstract

Giraffe anesthesia is considered high risk due to inherent challenges associated with their distinctive anatomy and physiology. This retrospective study (January 2014-January 2024) in zoo-housed giraffes (Giraffa camelopardalis) evaluated three thiafentanil-medetomidine-ketamine based protocols without the aid of a giraffe restraint device (GRD) for induction of anesthesia (66 events, 45 individuals, 15 facilities). Individuals were categorized as either adult (≥1 yr old) (n = 52) or juveniles (1 mon to <1 yr old) (n = 14). Three protocols included: thiafentanil 7.4 ± 1.1 µg/kg, medetomidine 15.1 ± 2.1 µg/kg, and ketamine 0.7 ± 0.1 mg/kg as sole agents (TMK; 45/66) or with the addition of butorphanol 0.02 ± 0.01 mg/kg in both a one-stage (TMKB; 9/66) or two-stage (MB-TK; 12/66) induction protocol. Adult giraffes were induced in indoor and outdoor holdings (typically padded, 42/52, 81%) or pasture setting (10/52, 19%), intubated, and ventilated. Time between darts was 13.3 ± 3.5 min for MB-TK. Adult median antagonist ratios were 5 mg atipamezole (range 4-15 mg) per 1 mg medetomidine IM, 32 mg naltrexone (range 10-214 mg) per 1 mg thiafentanil IM/SC/IV, and additional 3 mg naltrexone (range 0-34 mg) per 1 mg butorphanol IM/SC/IV. Median total anesthesia length (initial dart to antagonist administration) was 81.0 mins (range 26.0-162.0 mins) across all procedures. Time to recumbency varied between one and two dart protocols. Recovery parameters after antagonists included time to extubation (6.0 ± 4.6 min), head control (12.5 ± 8.6 min), and standing (21.9 ± 19.9 min). Adult mortality attributed to anesthetic complications was 2% (1/52), juvenile mortality was 0%. This study and others support a decreasing risk of mortality during giraffe anesthesia (0-2%), compared with historical publications.