Wounds in Sable Antelope During Chemical Immobilization
The savannah woodlands in southeastern Africa are home to the sable antelope (Hippotragus niger). There are also isolated populations of sable in Angola, Zimbabwe, northeastern Botswana, Mozambique, the northeastern part of the Caprivi Strip in Namibia and South Africa.1 The sable is considered an “edge” species that inhabits the woodland/grassland ecotone.2 They are known to be selective feeders, having a preference for fresh growth grasses. Sable are dependent on drinking water, and are seldom found far from water sources.
Four subspecies of sable have been identified: H. n. niger, H. n. kirkii, H. n. roosevelti and H. n. variani. Both male and female sable have large, curved horns, with those of the females being somewhat shorter and less curved. Sable bulls have glossy black coats (hence their name) contrasted by white undersides, rump, throat and facial markings. The females and young are a chestnut to dark brown in color.
Sable occur in herds of 10–30 individuals, but herds occasionally aggregate in numbers of up to 200 on a temporary basis.1 Subadult males, which are typically driven off as they mature, are sometimes associated with these herds and occasionally form bachelor groups. Like most other antelope, sable are timid but can become aggressive. In particular, the males can become dangerous if sufficiently provoked.
Risks for Wounds in Sable
Chemical immobilization events carry inherent risks to wildlife regardless of size or species, but these risks are often more pronounced when dealing with large species such as sable and other hoofstock in the field. During capture/chemical immobilization, these risks include such complications as capture myopathy, aspiration, dehydration, hypothermia, hyperthermia, respiratory depression and/or arrest and cardiac arrest. Many of these complications can come about as the direct result of chemical immobilization, either due to inadvertent overdose, comorbidities or the biochemical sensitivities of individual animals.
Wounds during capture events may be considered less critical than other potential complications, but they must be seriously considered and prepared for nonetheless. Wounds can occur as the result of an animal attempting to flee prior to immobilization, as it loses physical coordination during take-down after darting or (rarely) from the immobilizing darts themselves.3
One of the most common threats to wild animals is that of physical injury. Animals can incur severe injuries that kill them directly; in other cases, their injuries can affect them in ways that are indirectly fatal (e.g., reducing their ability to find food or to evade predators). Apart from human-related causes, these can come about as a result of myriad events, such as evading predators, fighting for mates or territory and accidents. Even when an animal doesn’t die as a direct or indirect result of an injury, it can be left in a permanently compromised state.4
When an animal suffers a wound during capture/chemical immobilization, ethical imperatives dictate that those undertaking the required research or wildlife management protocols make every effort to ensure that the animal is promptly treated so that it can make as complete a recovery as is possible.
Antelope and Wounds
Antelope comprise approximately 91 of the 140 or so known species of the Bovidae and Antilocapridae families. They vary widely in size; for example, the small royal antelope weighs an average of about four pounds, whereas the eland weighs up to 1,800 pounds.5 Despite being extremely widespread in geography and diverse in size, behavior and habitats, nearly all antelope are large hoofstock, and comparatively large as regards species typically encountered by researchers and wildlife managers in the field. Additionally, all antelope are prey animals, and have evolved with instincts and behaviors gauged to help them survive.
Consequently, sable and other antelope will invariably attempt to flee when approached in the field. Occasionally, this can result in injuries, either before or after the animal is darted. If the approach by humans is protracted (e.g., a long vehicle or helicopter chase), the risk of complications and injury can be increased manifold. When injuries occur, they are usually soft tissue injuries of varying severity.
Antelope have developed a number of methods to deal with predators, the most noteworthy of which is their speed and agility. If an antelope cannot evade its pursuer outright, it may try to hide in areas that are difficult to access. Some species will freeze in place to avoid being noticed, while others may stand their ground and defend themselves with their horns.4 The latter is most certainly the case with sable, as dominant males have been known to kill large predators—even lions—with their long horns whilst defending the herd.
Treatment of Wounds in Sable
Most injuries in sable that have been connected with capture events were experienced when an animal was attempting to flee human pursuers,3 and the most common injuries suffered are lacerations. While remote drug delivery via the dart itself is unlikely to result in a serious injury, darting can on occasion result in minor lacerations. Finally, in some cases the animal may need to be immobilized specifically for the treatment of a serious wound it has suffered due to other causes.
The first step in treating an injured sable is cleaning the wound. Small, shallow lacerations may be flushed with a commercial povidone-iodine or other scrub solution. Deeper wounds can be flushed with povidone-iodine diluted with saline, and should generally not be sutured to allow for drainage.3 The literature recommends high volume and, ideally, high-pressure irrigation unless the tissue is very delicate. Low-pressure irrigation is gentle to tissues and does not force bacteria deeper into the wound, but it does not debride as well as high-pressure irrigation, which can be performed with a pressurized fluid bag or a large syringe with an 18-gauge catheter.4
For suturing more superficial wounds that have been cleaned, a veterinarian should perform the procedure. If a veterinarian is not immediately available, non-absorbable sutures should be used.
Sable receiving a laceration prior to or during an anesthetic event should receive systemic antibiotics to reduce the possibility of infection. Procaine penicillin G combined with benzathine penicillin G is a common formulation is these instances. Long-acting oxytetracycine is also frequently used to treat hoofstock that have suffered lacerations.4
Given the inherent risks associated with chemical immobilization, there is no way to guarantee that injuries will not occur, especially in the field. However, the drug formulations currently available for immobilizing sable and other wildlife have been refined to a degree that eliminates much of the risk that existed years ago. With the right drug formulations, proper planning and safety precautions in place, experienced personnel can have the expectation of effective and incident-free chemical immobilization of sable in the majority of cases.
3Kreeger T., Arnemo, J., Raath, J. Handbook of Wildlife Chemical Immobilization, International Edition, Wildlife Pharmaceuticals, Inc., Fort Collins, CO. (2002).
4vetfolio.com: Remote Injection Systems. https://www.vetfolio.com/learn/article/remote-inj...
5Friend, M., Thomas, N. J. Field Manual of Wildlife Diseases. In: Field Manual of Wildlife Diseases, United States Geological Survey, 361-368.
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