BAM Deer Tranquilizer
Attention to detail in preparing for the capture or immobilization of deer may be the greatest predictor of a successful outcome. Anxiety, anticipation of danger, unfamiliar environments and crowded conditions can cause stress in animals and are usually present during a capture or immobilization event. These stressors may be mitigated by providing visual barriers, decreasing extraneous noise, having well-trained animal handlers on hand and utilizing proper equipment and facilities.
Whether the venue is out in the wild, an exotic animal ranch, a breeding farm, or a zoo, animals should be confined to the smallest enclosure in which they can be safely handled. Multiple gates to separate herd mates (if present) should always be provided. In the case of remote drug delivery scenarios, visual barriers should be used, so that the person shooting the dart is able to remain outside of the animal’s flight zone thereby reducing agitation of the animal and the herd prior to immobilization.1 If the immobilization area is a field or pasture, it should be assessed for potential hazards such as bodies of water, ditches, steep terrain and dense tree cover or brush. Contingency plans should be made to rescue animals should they become recumbent in such areas.
Hazards and Complications in the Field
Hyperthermia is a common problem during the immobilization of exotic ruminants and body temperature should be monitored throughout the procedure. A deer’s internal temperature may increase from physical exertion as well as psychological stress and fear and the response of the thermoregulatory center to changes in temperature is decreased by immobilization agents such as tranquillizers and sedatives. Hyperthermia may predispose the animal to metabolic complications such as capture myopathy, or if the body temperature increases above 109°F (43°C) death may occur.2 As the ambient temperature increases, it becomes more difficult for animals to dissipate heat and ideally a capture or immobilization should be planned for a cool, cloudy day with temperatures less than 77°F (25°C).3
Animals can be fasted for 12 to 24 hours to decrease the incidence of regurgitation and bloat; however, in a free-range setting this is often impossible. During the immobilization, care should be taken to protect the airway by maintaining the animal in sternal whenever possible (which will decrease the pressure of the abdominal viscera on the diaphragm) and by placing the head with the nose and mouth below the level of the ears to allow saliva or regurgitated rumen contents to drain.1
Capture myopathy is a syndrome that is not infrequently seen during capture and handling events in exotic small ruminants and is somewhat similar to exertional rhabdomyolisis in humans and horses. However, the pathogenesis of capture myopathy not only includes muscular activity but the sympathetic nervous and adrenal systems as well as perception of fear.1,2
Many immobilizing drugs as well as the act of recumbency can lead to hypoxemia in the anesthetized ruminant. If severe and left untreated, hypoxemia can lead to cardiac arrhythmias, organ function compromise, adverse metabolic changes (such as capture myopathy), and even death.1
Immobilizing Drugs for Deer
Given the above, and considering best practices, employing the safest and most efficacious immobilizing agents becomes an imperative. Xylazine, an α-2-adrenergic agonist, had been the most commonly used agent for chemical restraint of deer for this purpose in many countries. Xylazine is often combined with an opioid or ketamine to enhance its effectiveness. Pure opioid agonists, fentanyl, carfentanil and etorphine, are less effective than xylazine when used alone, and their use presents greater risk to operators and animals and is subject to more stringent legal restrictions. Some of the newer α-2 adrenergic agonists, detomidine and medetomidine, are more potent than xylazine, and bioavailability of specific α-2 adrenergic antagonists further enhances the usefulness of these drugs.1
With the advent of newer medications and custom formulations, drug combinations are frequently used to immobilize deer for capture or handling. Although the efficacy of various compatible and complementary drugs has been tested in clinical trials with deer, extensive negative side effects, impractical drug volume, and slow recovery from immobilization sometimes make these combinations less than ideal for routine field use.
Recently, it was discovered that the combination of butorphanol, azaperone, and medetomidine (BAM) provides safe and effective immobilization of wild and captive deer while minimizing many of the complicating factors detailed above.
Butorphanol (butorphanol tartrate) is a synthetically derived opioid agonist-antagonist analgesic of the phenanthrene series. In the United States, it is a U.S. Drug Enforcement Administration (DEA) class IV controlled substance.
Azaperone is a butyrophenone tranquilizer that causes tranquilization and sedation, antiemetic activity, reduced motor activity, and inhibition of CNS catecholamines.
Medetomidine (medetomidine hydrochloride), used alone and in combination with other drugs, has been shown to be useful for anesthesia and immobilization in zoo animals.1 Medetomidine is an α-2-adrenoreceptor agonist with sedative and analgesic properties.
BAM provides a low-volume, reversible alternative to other immobilizing drug combinations. In combination, the three drugs synergize to incorporate the most desirable qualities of each medication, and are ideal for most species of deer.
1VP Walsh & PR Wilson (2002) Sedation and chemical restraint of deer, New Zealand Veterinary Journal, 50:6, 228-236, DOI: 10.1080/00480169.2002.36318.
2Kreeger T., et. al. Handbook of Wildlife Chemical Immobilization, 3rd ed. Wheatland, WY, 2007.
3Miller B.F., et. al. Butorphanol-azaperone-medetomidine for immobilization of captive white-tailed deer. J Wildl Dis. 2009 Apr;45(2):457-67. doi: 10.7589/0090-3558-45.2.457. PMID: 19395755.
About NexGen Pharmaceuticals
NexGen Pharmaceuticals is an industry-leading veterinary compounding pharmacy, offering sterile and non-sterile compounding services nationwide. Unlike other veterinary compounding pharmacies, NexGen focuses on drugs that are difficult to find or are no longer available due to manufacturer discontinuance or have yet to be offered commercially for veterinary applications, but which still serve a critical need for our customers. We also specialize in wildlife pharmaceuticals, including sedatives and their antagonists, offering many unique options to serve a wide array of zoo animal and wildlife immobilization and anesthesia requirements.
Our pharmacists are also encouraged to develop strong working relationships with our veterinarians in order to better care for veterinary patients. Such relationships foster an ever-increasing knowledge base upon which pharmacists and veterinarians can draw, making both significantly more effective in their professional roles.
Disclaimer
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