Capture Myopathy in Barasingha Deer During Capture and Chemical Immobilization

Capture myopathy is a condition with high levels of morbidity and mortality that occurs chiefly in wild animals. It arises from stress and the physical exertion that often occurs with prolonged or short and intense pursuit and/or restraint.¹ Capture myopathy typically carries a grave prognosis, even with intervention and supportive treatment. While not as common as in wildlife, domestic animals can also be affected by capture myopathy.

Stress is an unavoidable part of the capture and translocation of wild deer. A malignant outcome of stress during capture operations, capture myopathy accounts for the highest number of deaths associated with wildlife translocation.²Sometimes, these deaths are indicative of how well animal welfare concerns were addressed during translocation. Since first recorded in 1964 in Kenya, many cases of capture myopathy have been reported, but the exact causes, mechanisms and treatment for this condition remain elusive.^2,3

Capture myopathy can occur in any animal under extreme stress, although it is thought that some species may be more predisposed to it than others due to their natural temperament and physiological characteristics.³ It has been most widely studied in ungulates and birds, although it is believed that it can potentially affect any captured wildlife species. It has also been observed in coyotes, badgers, primates, and many other species.²

Ungulates in North America that have been reported with this condition have included white-tailed deer, mountain goats, bighorn sheep, pronghorn antelope, bison, moose, and elk.^2,5

Barasingha Deer: Background and Biology

Like other deer species, barasingha deer (Rucervus duvaucelii) belong to the order Artiodactyla, which are hoofed mammals with an even number of toes on each foot. Deer are also commonly referenced as cervids. The barasingha deer is one of the most widely-recognized deer of the Indian subcontinent. Also called the swamp deer, it is found mostly in marshy, damp areas, such as reed beds and marshes. They occasionally dwell in open spaces, but this is usually very close to a source of water.

The Barasingha deer is extinct in both Bangladesh and Pakistan, where it once roamed freely. Today, there are fragmented populations in central and northern India, as well as southwestern Nepal.⁴ The name “Barasingha” is derived from the Hindi words for “twelve ends”, referencing this deer’s antlers, which can have from 12 to 20 tines. Barasingha deer have a lifespan of up to 20 years.⁵

The Barasingha is a large, long-legged deer, with a short head and long, broad ears. Larger stags may have an overall length of up to 71 inches (180 cm) and weigh up to 620 lbs (280 kg). Their coats are a yellowish-brown color, which darkens during the winter months. Some individuals have yellowish spots scattered over their coats. The hair around the deer’s neck may be longer, forming a shaggy mane.⁴

In their native range, Barasingha deer have a number of natural predators including the tiger; thus, they have developed an apprehensive, nervous manner and are always on high alert. They have a loud, barking call that they use to signal danger; this is said to be similar to the alarm call of the roe deer. Barasingha deer feed by day, but can also be found resting during the hottest times of the day. In the winter, large herds form, which dissipate during the summer into smaller herds composed chiefly of females and their fawns. During the summer, males live separately from females in small bachelor groups.^4,5

Female barasingha deer are monoestrous, and usually have a single fawn after eight months of gestation. Fawns are weaned at around six months, and the female is ready to breed again about a year after giving birth. Stags reach puberty at two years of age, and females reach puberty at 18 to 24 months.^4,5

In the late 1960s, the numbers of Barasingha deer in India decreased drastically due to hunting, habitat loss and disease. It was brought back from the verge of extinction over several decades through successful breeding programs and conservation practices. Habitat improvement and captive breeding led to a substantial increase in the population.⁴ Today, their populations are no longer in danger, and the Barasingha has been introduced to many areas, including the United States, where they are hunted on carefully-controlled ranches and reserves.

Clinical Signs of Capture Myopathy

Capture myopathy can occur naturally when a barasingha deer is attempting to avoid predation. For the purposes of this discussion however, capture myopathy will be the result of these animals being captured and/or immobilized via chemical means. Like all deer, barasingha deer are adapted to escape from predators, but they are not adapted to struggle for long periods of time in human-devised restraints.³ 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 can result.²Clinical signs of capture myopathy in barasingha deer can vary depending on the circumstances and the cause of exertion.² The method of capture and restraint is also a determinant in occurrences of capture myopathy. The available literature states that capture myopathy may result in sudden death, or that clinical signs may develop hours, days, or up to two months following capture.⁴ The clinical signs during early onset include elevated respiratory rate, heart rate, and body temperature.^1,3 Body temperature increases during exertion, with higher temperatures being associated with death due to capture myopathy. The increase in body temperature can be above 42°C.⁴ Muscle spasms, stiffness and lameness are also clear signs of capture myopathy. 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 affected.^2-4 Death of the animal usually follows. Upon necropsy, light-colored skeletal and cardiac muscle is indicative of capture myopathy being the cause of death (see photo).

Preventing Capture Myopathy in Barasingha Deer

Since there is no treatment for capture myopathy, prevention is the best method of avoiding the development of this condition. Care should be taken with the handling of animals that tend to be more susceptible to capture myopathy. An anesthetic protocol consisting of good anesthetic agents can aid significantly in preventing capture myopathy in deer. In the case of wild deer (as opposed to a zoo, farm or preserve), the remote delivery of anesthetic agents is considered a superior methodology to trapping.

The capture team should be thoroughly aware of the risks of capture myopathy and make every effort to prevent its occurrence. Barasingha deer 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.⁵ Capture methods that minimize animal stress, struggling and handling time should be utilized.

Appropriate protocols for the chemical immobilization of barasingha deer may vary depending upon the animal’s size, age, sex and general health (if known), 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 barasingha deer.³

¹Breed D, Meyer LCR, Steyl JCA, Goddard A, Burroughs R, Kohn TA. Conserving wildlife in a changing world: Understanding capture myopathy-a malignant outcome of stress during capture and translocation. Conserv Physiol. 2019 Jul 5;7(1):coz027. doi: 10.1093/conphys/coz027. PMID: 31304016; PMCID: PMC6612673.
²Williams, 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.
³Blumstein, 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.
⁴worlddeer.org.
⁵animalia.bio.
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.