Capture Myopathy in Llamas During Capture and Chemical Immobilization

The llama (Llama glama) is a domesticated pack animal that has been used for centuries by Andean cultures in the mountains of South America. Members of the camel family (Camelidae), llamas are related to dromedary camels, Bactrian camels, wild Bactrian camels, alpacas, vicuñas, and guanacos.¹ It is believed that llamas were derived primarily from the latter species.

Llamas and their various South American cousins are also referenced as a group as lamoids or New World camelids. These animals lack the characteristic back humps of Old World camelids. Interestingly, many lamoids are able to breed with one another. According to the fossil record, the ancestors of modern llamas evolved in North America 40 million years ago, migrating to South America approximately 3 million years ago. Other prehistoric camelids migrated west via the Bering land bridge, later becoming modern camels. Scientists believe that at the end of the last ice age (10 to 12 thousand years ago), llamas became extinct in North America.¹

Today, the majority of llamas live in Argentina, Bolivia, Chile, Ecuador, and Peru. Over the last 40 years, South American exporters have been transporting llamas to farmers and breeders around the world, primarily North America, Australia, and Europe. As a result, llamas have become popular among farmers, breeders, and exotic pet enthusiasts.²

The llama is the largest of the New World camelids, and comes in a variety of sizes and colors, such as brown, white, black, grey, piebald or spotted. The soft inner hairs of their fleece are highly valued for clothing and knitting. The outer hairs of their fleece are coarser and are used to make ropes, rugs, and handicrafts. Adult llamas range in height from 5-1/2 feet to 6 feet tall and weigh between 290 to 440 pounds.¹ They have short tails and large, banana-shaped ears. Their feet are narrow and padded on the bottom, allowing these animals to comfortably navigate rough mountain terrain.²

Llamas are social animals that do very well living in herds. Females are called “dams” or “hembras,” while males are called “studs” or “machos.” Castrated males are called “geldings.” In South America, llamas are sometimes used as livestock guards for flocks of sheep, with geldings typically being trained for these missions.³ Llamas communicate through a variety of humming sounds, and it is said that they can distinguish between different vocalizations. When they recognize danger, llamas will let out a shrill moan to alert members of the herd.

Despite the llama’s pleasant demeanor and tractability, it has been recommended that llama owners and farmers refrain from oversocializing these animals, since it can lead to something called “berserk llama syndrome.” This is reported as a psychological condition that affects male llamas when they become too comfortable with humans, see them as fellow herd members and try to dominate them.³

Llamas graze primarily on grass, regurgitating their food and chewing it as cud. Unlike cows however, they are pseudo ruminants with a three-chambered stomach (unlike true ruminants such as cows, which have four-chambered stomachs). Llamas have a very long large intestine which allows them to go for long periods without water.² Llamas breed in the late summer and fall. Their gestation period is approximately 11 months, after which the female gives birth to one young.³Llamas have an average lifespan of 20 years.

Llamas and Capture Myopathy Risks

Capture myopathy (CM) is a dangerous condition that can occur in both wild and domestic animals, and involves muscle damage resulting from extreme exertion, struggle, or stress. It is also known as exertional myopathy, overstraining disease and exertional rhabdomyolysis.⁴ Capture myopathy most often occurs 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.⁵ This is of particular ethical concern in cases when it is a cause of death in animals that are in the care of humans.

Capture myopathy can occur in any animal under extreme stress, although it is believed that some species may be more predisposed to it than others.⁶ It has been most widely studied in ungulates and birds, although it is believed that it can potentially affect any captured species. It has also been observed in coyotes, badgers, primates, and many other species.⁵

Clinical Signs of Capture Myopathy

Capture myopathy can occur naturally when an animal is attempting to avoid predation, but since llamas have few predators and are largely domesticated, for the purposes of this discussion, it will be the result of these animals being captured and/or chemically immobilized. Like other animals, llamas are not adapted to struggle for long periods of time in human-constructed restraints.⁶ When animals overexert themselves (e.g., attempting to flee a capture team or struggling in a trap) to the extent that physiological imbalances develop and result in severe muscle damage, capture myopathy results.⁵Increased environmental temperatures and repeated chemical immobilization can increase the risk of animals suffering from capture myopathy.⁷

Clinical signs of capture myopathy in llamas can vary depending on the cause of exertion.⁵ Thus, the method of capture and restraint is also a determinant in occurrences of CM. 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 of CM include elevated respiratory rate, heart rate, and body temperature.^4,6 Body temperature increases during exertion, with higher temperatures being associated with death due to CM. The increase in body temperature can be above 42°C.⁴

During a chemical immobilization event, 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 severely affected.^5-7 Death of the animal usually follows. If an animal survives the acute stage of the condition, scarring of heart and skeletal muscle tissue may permanently debilitate the animal.⁷ Upon necropsy, light-colored skeletal and cardiac muscle is indicative of capture myopathy being the cause of death.

Preventing Capture Myopathy in Llamas

Since there is no treatment for capture myopathy, prevention is the best method of avoiding this condition. Care should be taken in case of 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 llamas. In such cases, the remote delivery of anesthetic agents is a superior methodology to trapping an animal prior to sedation or anesthesia being used.

Teams handling llamas should be aware of the risks of capture myopathy and make every effort to prevent its occurrence. Llamas 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.^8-10 Capture methods that minimize animal stress, struggling and handling time should be utilized. It has been reported that using a combination of Xylazine HCL and Ketamine HCL can decrease the chance of capture myopathy, but this is by no means a guarantee of avoiding this condition in llamas.⁶

¹britannica.com.
²nationalgeographic.com.
³animaldiversity.org.
⁴Friend, M., Thomas, N. J. Field Manual of Wildlife Diseases. In: Field Manual of Wildlife Diseases, United States Geological Survey, 361-368.
⁵Williams, 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.
⁶Blumstein, 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.
⁷Kohn, Tertius. (2013). Capture myopathy mystery.
⁸Businga 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.
⁹veteriankey.com.