Capture Myopathy in Sable Antelope
The sable (Hippotragus niger) is one of Africa’s most visually striking antelopes. Its compact, sturdy build, erect mane and thick neck has led to its inclusion in the “horse antelope” genus (Hippotragini).1 Both male and female sable have scimitar-shaped horns, although those of the females tend to be slightly shorter and less curved. Sable bulls have glossy black coats contrasted by white undersides, rump, throat and facial markings. The females and young are a chestnut to dark brown in color. In the H. niger niger subspecies (which inhabit areas south of the Zambezi River), females can appear very dark.
The range of the sable includes the southern savanna from central Tanzania to South Africa.2 It inhabits the ecotone between wooded savannas and grasslands. During the rainy season from September to April, sable forage grasses and foliage of the woodlands. During the dry season, they come out onto grasslands where it grazes on green plants that emerge after the annual fires.
Sable are territorial but sociable, with herds of females and young of over 50 animals congregating in ranges of 4 to more than 20 square miles. In some areas, herds can be much larger. Female offspring usually remain in their home ranges, but adult males drive out subadult males as they mature. The banished males will join bachelor herds until they are ready to compete for their own territory.2
Capture Myopathy Risks for Sable
Capture myopathy (CM) is a very serious condition that occurs in both wild and domestic animals wherein muscle damage results from extreme exertion, struggle, or stress. CM is also known as exertional myopathy, overstraining disease and exertional rhabdomyolysis.3 Most often, capture myopathy comes about as a result of capture, transport or chemical immobilization, but it can also be the result of other natural causes of stress, such as in prey animals attempting to avoid or struggling with predator animals.4
Capture myopathy can occur in any animal under extreme physical stress, although it is thought that some species may be more predisposed to it than others due to their temperament and physiological characteristics.5 It has been most widely studied in ungulates and birds, although it is believed to potentially affect any captured wildlife species. Capture myopathy has also been observed in coyotes, badgers, primates, and many other species.4 It is believed that capture myopathy can even occur in fish and amphibians.3
Causes and Clinical Signs of Capture Myopathy in Sable
Capture myopathy in sable can occur naturally when these animals are attempting to avoid predation, but for the purposes of this discussion, capture myopathy will be the result of an individual animal being captured and/or immobilized with or without chemical means being involved. Sable, like other antelope, are adapted to escape from predators, but they are not adapted to struggle for long periods of time in artificial restraints.5 When animals overexert themselves (e.g., struggling in a trap) to the extent that physiological imbalances develop and result in severe muscle damage, capture myopathy results.4Increased temperatures (ambient and/or internal) and repeated chemical immobilization can increase the risk of sable developing capture myopathy.6
Source/Credit: Oxford University Press
Clinical signs of capture myopathy in sable can vary depending on the cause of exertion.4 The method of capture and restraint is also a determinant in occurrences of capture myopathy. Capture myopathy may result in sudden death, or clinical signs may develop hours, days, or up to two months following capture.6 Early onset clinical signs include elevated respiratory rate, heart rate, and body temperature.3,5 Body temperature increases during exertion, and higher temperatures are associated with death due to CM.6
Muscle spasms, stiffness and lameness are also clear signs of CM. Animals often become recumbent and may stumble. If dark red-colored urine is noted, this is an indication that the animal's muscles are breaking down and that its kidneys have been severely affected.4-6 Death of the animal usually follows. Upon necropsy, light-colored skeletal and cardiac muscle is indicative of capture myopathy being the cause of death.
Preventing Capture Myopathy in Sable
Since there is no treatment for capture myopathy, prevention is the best method of avoiding this condition. Animals that tend to be more susceptible to capture myopathy should be handled with extra caution. An anesthetic protocol consisting of safe and effective anesthetic agents can aid significantly in preventing capture myopathy in sable. Considering these factors, the remote delivery of anesthetic agents is a superior methodology to trapping an animal prior to the anesthetic event.
The team in the field should be thoroughly aware of the risks of capture myopathy and make every effort to prevent its occurrence. Sable (and indeed, any wild species) should only be captured when necessary, and the negative effects that capture may have on an animal's health should always be considered before beginning a capture or initiating an anesthetic event.7 Capture methods that minimize animal stress, struggling and handling time should be utilized. Appropriate methods may vary depending on the subspecies, so research can be helpful in identifying the ideal capture method. It has been reported that using a combination of Xylazine HCL and Ketamine HCL can decrease the chance of capture myopathy, but this is not a guarantee of avoiding capture myopathy in any species.5
3Friend, M., Thomas, N. J. Field Manual of Wildlife Diseases. In: Field Manual of Wildlife Diseases, United States Geological Survey, 361-368.
4Williams, E. S., Thorne, E. T. 1996. Exertional Myopathy (Capture Myopathy). Noninfectious Diseases of Wildlife, Second Edition, 181-193 Iowa State University Press, Ames, Iowa, USA.
5Blumstein, D., et. al. The evolution of capture myopathy in hooved mammals: a model for human stress cardiomyopathy?Evolution, medicine, and public health vol. 2015,1 195-203. 21 Jul. 2015,
6Kohn, Tertius. (2013). Capture myopathy mystery.
7Businga NK, Langenberg J, Carlson L. Successful treatment of capture myopathy in three wild greater sandhill cranes (Grus canadensis tabida). J Avian Med Surg. 2007 Dec;21(4):294-8. doi: 10.1647/2005-013R1.1. PMID: 18351009.
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