Abstract
Immobilization of giraffe and the associated risks have been previously described in the literature.1,2,5 The use of medetomidine and ketamine for immobilization of free-ranging giraffe has also been described.3 This report summarizes the immobilization of captive giraffe using this same drug combination.
Fifteen captive giraffe (Giraffa camelopardalis) were immobilized on thirty occasions using a combination of intramuscular medetomidine and ketamine. All but one very ill animal recovered from anesthesia. Two animals died the following day from presumed anesthetic-related causes. One animal was euthanatized four days following immobilization due to severe ileus and clinical deterioration. Accurate weights were not obtained on the majority of animals and, therefore, doses are summarized by age group (Table 1).
Table 1. Summary of doses of medetomidine and ketamine used to immobilize captive giraffe at various ages
|
# Events
|
Age
group
|
Estimated
weight range
|
Initial drug doses
|
Comments
|
|
6
|
2.5–6.5 months
|
100–160 kg
|
8–9 mg meda
00–200 mg ketb
|
This dose range worked well for this age group.
|
|
4
|
8–12 months
|
272–295 kg
|
18–21 mg med
220–400 mg ket
|
This dose range worked well for this age group.
|
|
3
|
20–28 months
|
370–540 kg
|
20-25 mg med
300 mg ket
|
This dose worked well for this age group but
would recommend 20 mg med and 300–500 mg ket.
|
|
17
|
8–22 years
|
700–1100 kg
|
40–90 mg med
450–1500 mg ket
|
Recommend 40–50 mg med and
800–900 mg ket for an adult female;
50–70 mg med and 1000–1200 mg ket
for an adult male; however, lower
doses may also be effective and should
be considered for smaller, ill, or compromised animals.
|
aMedetomidine
bKetamine.
The first drug effect (time from initial injection to initial drug effect) ranged from 2–6 minutes (average = 4 minutes). Twenty-six giraffe became recumbent following the initial dose of medetomidine and ketamine. The time from the initial injection to recumbency ranged from 4–38 minutes (average = 13 minutes). Increasing doses of medetomidine did not necessarily decrease the time to recumbency nor did it ensure animals became recumbent. Four giraffe received additional intramuscular ketamine and/or medetomidine prior to becoming recumbent. All four animals were leaning against a wall or were head-pressing and this posture likely prevented recumbency. Once recumbent, supplements included intravenous medetomidine, intravenous ketamine, intravenous guaifenesin (GGE), intravenous propofol, or isoflurane via facemask, or endotracheal intubation. Intravenous GGE or propofol is preferred, although transient apnea was observed in a few cases following rapid propofol administration.
The duration of the anesthetic events (time from initial drug dosing to the administration of the antagonist) ranged from 21–145 minutes with an average of 82 minutes. Atipamezole or a combination of atipamezole and yohimbine were used to antagonize the effects of medetomidine. The preferred route for atipamezole administration is intramuscular, and it is recommended that giraffe be held in lateral recumbency for approximately 15 minutes prior to allowing attempts to stand. The recommended dose is approximately 200 µg/kg or up to five times the amount of medetomidine in milligrams. Several animals stood and fell during the recovery period. Animals usually remained calm in a sternal position before re-attempting to stand. A few animals required additional atipamezole due to incomplete reversal. Some animals showed evidence of resedation or drug recycling 10–28 hours following atipamezole administration. Signs of medetomidine resedation included decreased awareness of the animal’s surroundings, dull eyes, inappetance, salivation, tongue drooping, excessive licking, ataxia, leaning against walls, and even recumbency. Animals responded positively to the administration of intramuscular atipamezole.
Acknowledgments
The authors gratefully acknowledge the contributions of Dr. Mitch Bush and the participation of the veterinarians and staff members from the Fossil Rim Wildlife Center, National Zoo, Riverbanks Zoological Park and Botanical Garden, San Diego Zoo’s Wild Animal Park, and Zoo Atlanta.
Literature Cited
1. Bush M. Anesthesia of high-risk animals: giraffe. In: Fowler ME, ed. Zoo and Wild Animal Medicine Current Therapy 3. Philadelphia, PA: WB Saunders; 1993:545–549.
2. Bush M, Grobler DG, Raath JP. The art and science of giraffe (Giraffa camelopardalis) immobilization/anesthesia. International Veterinary Information Service. www.ivis.org. 2002.
3. Bush M, Grobler DG, Raath JP, Phillips LG, Stamper MA, Lance WR. Use of medetomidine and ketamine for immobilization of free-ranging giraffes. JAVMA. 2001;218:245–249.
4. Morkel P. Chemical capture of the giraffe (Giraffa camelopardalis). In: McKenzie AA, ed. The Capture and Care Manual: Capture, Care, Accommodation and Transportation of Wild African Mammals. Pretoria, South Africa: Wildlife Decision Support Services CC and the South African Veterinary Foundation; 1993:601–607.