Chemical Immobilization and Sedation in the Llama
Today, researchers, veterinarians and wildlife management personnel are able to obtain certain types of biological data without the need to physically handle animals due to the development of non- and minimally invasive medical procedures. Some information, however, can still only be obtained by capturing individual animals.1 Captures are also important for relocation and for marking individuals in the case of some studies.
Global positioning system (GPS) collars, heat sensitive transmitters and advanced physiological monitoring equipment now allow detailed research on many species, but still require the initial capture and manipulation of individual animals.2
The Llama: Background and Biology
The llama (Lama glama) is probably the most widely-recognized of the world’s camelids next to the camel itself. The llama is a large camelid that originated in North America about 40 million years ago. In fact, it is the largest of the New World camelids or lamoids, a group that includes llamas, alpaca, guanaco and vicuñas.
Fossil evidence indicates that all camelids originated in North America, and it is believed that one group moved north, crossing the Bering land bridge and evolving into camels about three million years ago, while others migrated south and became New World camelids.3 By the end of the last ice age (approximately 12,000 years ago) camelids were extinct in North America.
The most obvious difference between lamoids and camels is that the former lacks the characteristic back hump of the camel. While llamas and alpacas are often mistaken for one another, differentiating characteristics between llamas and alpacas are that llamas are around 60% larger.4 Llamas average 45 inches in height at the shoulder, with adult males weighing between 300 and 400 pounds, and adult females weighing between 230 and 350 pounds.4,5 The average adult alpaca weighs slightly over 100 pounds. Alpacas also have a more luxurious fleece than llamas, which has led to an explosion in alpaca farming in recent years.
The llama’s natural environment in the South American Andes is at high altitude and is relatively cool. Like sheep, llamas require shearing through summer to prevent heat stroke. On farms in more temperate regions, a llama’s health will benefit from periodic shearing if they live where summers are hot. A llama needs about three inches of its fleece for winter warmth, so a llama sheared to one inch in the spring can grow an adequate coat by the time winter comes.5
In their natural environment in the Andes, the llama is a grazer and browser with a diet consisting of grasses and leaves. Llamas are adaptive feeders, however; on farms, they will eat grasses, shrubs, trees and hay. Three to five llamas can be grazed per acre, and a bale of hay will feed an adult llama for around a week.4
Drugs Used for the Chemical Immobilization of Llamas
The capture methodology employed is a factor in the effects of capture on any animal. In this regard, the literature agrees that captures by remote delivery of immobilizing drugs via darting lower a llama’s stress levels, thus decreasing the capture effects and risks compared to other techniques.6 This is a chief reason why chemical immobilization is becoming a preferred capture method, particularly in the case of larger mammals.
The three classes of immobilization drugs that are used on llamas include opioids, cyclohexamines and neuroleptics.
Opioids
- The most potent drugs available for immobilization
- A major advantage is the availability of specific antagonists
- Reduced volume of drugs are typically required
- The only class of drugs practical for remote immobilization of large animals
- Potentially toxic to humans
Cyclohexamines
- Also known as dissociative agents
- Produce altered consciousness
- Dissociate mental state from environmental stimulation
- Retain many vital reflexes
- The animal cannot walk but can move tongue, blink, swallow
- The animal may feel some pain
- Common cyclohexamines include Ketamine, tiletamine
- Cyclohexamines should not be used alone and are not reversible
- Should be used in conjunction with other drugs, such as neuroleptics
Neuroleptics
- Also referred to as tranquilizers
- Produce calmness and relaxation
- Do not cause loss of consciousness or alleviate pain perception
- Can cause death before they cause loss of consciousness
- Used in conjunction with other drugs (e.g., cyclohexamines)
- Common neuroleptics include zolazepam, diazepam, xylazine
- Common reversal agents include yohimbine, tolazoline
Chemical Immobilization Techniques for Llamas
Less stress on a llama is likely to occur in a zoo or on a farm than in the field, since animals in these settings tend to be far more acclimatized to human handling. Additionally, since llamas have been so heavily domesticated, most are far less prone to capture stress than other hoofstock species.
When working with llamas that are cooperative, intramuscular hand injection can be employed. When hand injecting, a rapid delivery that minimizes risk to the handler and animal is essential. Pole syringes are also widely used for this purpose, since these afford greater distance than approaching an animal for a hand injection without resorting to remote delivery systems. As with hand injection, larger bore needles should be used to ensure complete drug delivery.
Remote chemical immobilization can be carried out by approaching a llama and shooting a dart from a vehicle or from the ground. While this can significantly reduce stress compared to physical capture methods, it still impacts the llama’s stress levels. A frightened llama will have an increased heart rate, higher levels of cortisol and other stress-related biochemicals.6 An approach on foot will produce lower stress levels in llamas, because they will be less frightened than if a noisy vehicle is used.Intubation is recommended for any llama that need to be anesthetized for longer than 20 minutes.6 If the llama’s skin has been breached by anything larger than a hypodermic needle during procedures, analgesia will be required. Invasive surgeries should be conducted using general anesthetics with the animal at a surgical plane; intraoperative analgesia that continues after anesthetic recovery should be provided in some form.1 For analgesic drugs, doses and frequencies of administration are more difficult to gauge, even with close clinical observation for discomfort.7 These observations can be even more difficult to make in the field than in a clinic or zoo setting, compounding the difficulty in such assessments.
Most of the opioid analgesics (Buprenorphine, Fentanyl, Butorphenol, Oxymorphone, etc.) are no longer effective 12 hours after administration. Longer‐lasting, non‐steroidal anti‐inflammatory analgesics (NSAIDs) such as Meloxicam, Carprofen, Flunixin, Ketoprofen,etc. have longer durations of action than opioids, and can be administered in conjunction with opioids to increase potency of effect and duration of action.7
Reversal Agents for Llamas
Reversal agents are often required to neutralize sedation or anesthetic agents, thus allowing the llama to completely recover from being anesthetized. This is even more important in the field than in a clinic, farm or zoo setting, because a chemically-compromised llama will be in danger of injury and other hazards.
The duration of anesthesia in the llama will be influenced by the drugs used, age, sex, body weight, procedure(s) performed and the amount of stimulus during the procedure. Due to the variety of factors that influence duration of anesthesia, the literature maintains that anesthetic drugs should be titrated to effect. If anesthesia is being maintained by a gas anesthetic (e.g., isoflurane), titration of anesthetic depth can be controlled almost immediately by adjusting the amount of anesthetic gas being administered to the animal.7
Conversely, injectable anesthetics and sedatives do not have this flexibility. Once a dose has been administered, it cannot be “dialed-back” to facilitate the end of anesthesia to coincide with the end of the procedure.8 In such cases, reversal drugs can be used to bring about the desired effect.
Naltrexone hydrochloride is an opioid receptor antagonist that is used in veterinary medicine to block receptors as a reversal agent for opiate agonists such as butorphanol.
Atipamezole is a synthetic α2-adrenergic antagonist. Developed to reverse the actions of compounds such as medetomidine and dexmedetomidine, atipamezole safely and reliably reverses the effects of these compounds and is widely used in small and large animal practices, as well as in wildlife applications.9
Great care has been taken with chemical immobilization protocols and drug development in recent years to ensure that these are within safety margins through the use of novel anesthetics, including combinations of true anesthetics, neuromuscular blockers and tranquilizers.2 As a result, modern chemical immobilization techniques have dramatically reduced the side-effects of drugs and mortalities. The use of antagonists to anesthetics is now widely employed; this avoids the undesirable and potentially harmful effects of drugs and facilitates the speedy of animals’ recovery from chemical immobilization.1,2
The drug formulations available for immobilizing llamas and other large wildlife species 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 llamas.
1Brivio F, Grignolio S, Sica N, Cerise S, Bassano B (2015) Assessing the Impact of Capture on Wild Animals: The Case Study of Chemical Immobilisation on Alpine Ibex. PLoS ONE 10(6): e0130957.
2Powell RA, Proulx G (2003) Trapping and marking terrestrial mammals for research: integrating ethics, performance criteria, techniques, and common sense. ILAR J 44: 259–276.
7Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed.
8Nielsen, L. Chemical Immobilization of Wild and Exotic Animals. (1999) Ames, Iowa, Iowa State University Press.
9Lance, W. Exotic Hoof Stock Anesthesia and Analgesia: Best Practices. In: Proceedings, NAVC Conference 2008, pp. 1914-15.
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
The information contained in this blog post is general in nature and is intended for use as an informational aid. It does not cover all possible uses, actions, precautions, side effects, or interactions of the medications shown, nor is the information intended as medical advice or diagnosis for individual health problems or for making an evaluation as to the risks and benefits of using a particular medication. You should consult your veterinarian about diagnosis and treatment of any health problems. Information and statements have not been evaluated by the Food and Drug Administration ("FDA"), nor has the FDA approved the medications to diagnose, cure or prevent disease. Medications compounded by NexGen Pharmaceuticals are prepared at the direction of a veterinarian. NexGen Pharmaceuticals compounded veterinary preparations are not intended for use in food and food-producing animals.
NexGen Pharmaceuticals, LLC does not recommend, endorse or make any representation about the efficacy, appropriateness or suitability of any specific dosing, products, procedures, treatments, services, opinions, veterinary care providers or other information that may be contained in this blog post. NEXGEN PHARMACEUTICALS, LLC IS NOT RESPONSIBLE NOR LIABLE FOR ANY ADVICE, COURSE OF TREATMENT, DIAGNOSIS OR ANY OTHER INFORMATION, SERVICES OR PRODUCTS THAT YOU OBTAIN THROUGH THIS BLOG POST.