WildLife Group
of the SAVA
Using BAM as an Alternative
to Opioids in Captive Blesbok
Liesel Laubscher
Blesbok (Damaliscus pygargus phillipsi) are gregarious,
medium-sized antelope that inhabit the open grassland
of South Africa. As a favoured species amongst game
ranchers, blesbok are regularly sold and translocated
with chemical immobilisation most commonly used
as it allows for safe handling of the animals. Chemical
immobilisation has become an essential part of
research, the treatment of sick or injured animals and
capture operations. Medicine combinations used for
the immobilisation of blesbok are generally opioid-
based with etorphine being widely used. Thiafentanil
may also be used, with some practitioners claiming that
a mixture of etorphine and thiafentanil provides better
induction than etorphine alone. A number of sedatives
and tranquilizers can be included in the immobilising
mixture as well.
In antelope species, potent opioids are frequently
reported to be associated with hyperthermia,
respiratory depression, poor muscle relaxation,
and capture myopathy. The use of a mixture of
butorphanol, azaperone and medetomidine (BAM)
provides a potentially useful alternative. Butorphanol
is a synthetic opioid analgesic agent (partial agonist-
antagonist) that is three to five times more potent than
morphine. It can be combined with alpha2-adrenergic
agonists to produce profound sedation or light general
anaesthesia. Azaperone is a short-acting neuroleptic
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sedative that belongs to the class of butyrophenones.
It is often used in combination with opioids and
alpha2-agonists to reduce capture and handling stress
and to improve inductions. Medetomidine is a potent
alpha2-agonist with sedative and analgesic properties.
In combination with butorphanol, it provides smooth
inductions and good muscle relaxation.
Internationally, the combination of BAM reportedly
provides safe and reversible immobilisation in white-
tailed deer, rocky mountain elk, Nubian ibex, bison,
bighorn sheep and caribou 1–80.58+/-0.1 mg/kg.
Wildlife Pharmaceuticals set out to determine if this
combination could also provide safe immobilisation
in captive blesbok. The research team wanted to
compare induction times when BAM (Bamanil, Wildlife
Pharmaceuticals (Pty) Ltd., White River, South Africa)
was used on its own as well as when it was used in
combination with hyaluronidase.
Hyaluronidase is a proteolytic enzyme that is thought
to improve medicine absorption in the muscle via
enzymatic break-down of the interstitial barrier
between cells. This in turn breaks down the intercellular
matrix (responsible for tissue integrity) and allows
medicines to reach the central compartment much
faster.
The study used sixteen blesbok (four males, ranging in
weight from 52.5 – 69.3 kg and twelve females, ranging