Chemical Immobilization and Sedation in Camels
Despite the fact that the majority of camels in the world have been largely domesticated, research, zoos and management programs can require the capture and manipulation of these animals. The development of non- and minimally invasive procedures over the years have allowed researchers, veterinarians and management personnel to obtain certain types of data without the need to handle animals. Some information, however, can only be obtained by capturing animals.1 Captures are also important for marking individuals in the case of some studies.
Technological advances such as global positioning system (GPS) collars, heat sensitive transmitters and advanced physiological monitoring equipment now allow detailed research on species such as camels, but still require the initial capture and manipulation of individual animals.2
The Camel: Background and Biology
Camels are included in any of three species of large hoofed ruminants that inhabit northern Africa, the Middle East and Asia and which are known for their ability to go for long periods without water. The Arabian, or dromedary camel (Camelus dromedarius) has one back hump, while the domesticated Bactrian camel (C. bactrianus) and the wild Bactrian camel (C. ferus) have two humps. Approximately 90% of the world's camels are dromedary camels, and nearly all of these are domesticated.3
Camels are native to northern Africa and southwestern Asia, and dromedary camels were introduced into Australia during the 19th Century to aid in the exploration of that continent. Bactrian camels are native to the Gobi Desert in China and the steppes of Mongolia. Arabian camels have been domesticated for approximately 3,500 years and have been long valued as pack animals that can carry large loads (over 100 lbs.).4 Camels have long been used by humans for their wool, milk, meat and leather.5
All three camel species are approximately 10 feet long and 6-1/2 feet high at the hump. Males typically weigh in at approximately 900 to 1,400 pounds; females are about 10% smaller and lighter. Their color is light brown to medium gray. Bactrian camels are slightly darker and stockier, and have more hair than wild Bactrian camels or dromedary camels.4
Camels are diurnal and spend much of their days eating. Their upper lips are split in half, with each half moving independently. This allows them to forage very near to the ground. Their lips can break off and eat tough vegetation, and it has been reported that some camels will even eat fish.5
Camels can go a week or more without water, and can last for several months without food. The humps on their backs store up to 80 pounds of fat, which they break down into energy when food is not available.4,5 When camels do drink water, they can consume 30 gallons of in less than 15 minutes without ill effects.
All species of camel are seasonal breeders with females coming into heat during the breeding season. This normally occurs during the winter months, from November to March.3
Drugs Used for Chemical Immobilization of Camels
The effects of immobilization on camels can differ considerably according to the capture methodology employed. In this regard, the relevant published research agrees that captures by remote delivery of immobilizing drugs via darting lower an camel’s stress levels, thus decreasing the subsequent capture effects compared to other techniques.6 This is a chief reason why chemical immobilization is becoming a preferred capture method, particularly concerning large mammals such as camels.
The three classes of immobilization drugs that are used on camels 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
In a zoo setting, less stress on camels is likely to occur than in the field, as zoo animals tend to be far more acclimatized to humans and procedures. Additionally, since camels have been so heavily domesticated, most are less prone to capture stress than other hoofstock species.
In some cases, intramuscular hand injection can be used when working with camels that are cooperative, or those that have been cornered in enclosures. When hand injecting, rapid delivery while minimizing risk to the handler or animal is essential. Pole syringes are also widely used for this purpose; these afford greater distance than approaching an animal for a hand injection without resorting to remote delivery systems. Drug delivery by pole syringe requires manual injection follow through to administer the drug, as the handle is usually an extension of the plunger. As with hand injection, larger bore needles should be used to ensure complete drug delivery.
Remote chemical immobilization is usually carried out by approaching camels and shooting a dart from a helicopter, an off-road vehicle or from the ground. While this can significantly reduce stress compared to physical capture methods, it still impacts the camel’s stress levels. A frightened camel will have an increased heart rate, higher levels of cortisol and other stress-related biochemicals.6 An approach from the ground tends to produce even lower stress levels in camels, because animals are generally less frightened than if a noisy vehicle is used.
Analgesia will be necessary if the camel’s skin has been breached by anything larger than a hypodermic needle, including biopsy instruments. 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 to every surgical patient.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. Intubation is recommended for camels that need to be anesthetized for longer than 20 minutes.
Most of the opioid analgesics (Buprenorphine, Fentanyl, Butorphenol, Oxymorphone, etc.) will not be effective after 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 Camel Sedation and Anesthesia
Whether general anesthesia or sedation has been used, reversal agents are often required to neutralize sedation or anesthetic agents, thus allowing the camel to completely recover from being anesthetized. This is even more important in the field than in a clinic or zoo setting, because a chemically-compromised animal will be in danger of injury and other hazards.
Duration of anesthesia in the camel is 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 always 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. In addition, anesthetic duration can be extended for as long as the anesthetic gas is administered.7
Conversely, injectable anesthetics and sedatives do not have this flexibility. Once a dose has been administered, it cannot be “un-administered” to facilitate the end of anesthesia to coincide with the end of the procedure.8 In such cases, reversal drugs are used to bring about the desired effect.
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
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.
Given the existing concerns in the area of conservation and humane treatment, great care has been taken with chemical immobilization protocols and drug development to keep these within safety margins through the use of novel anesthetics, including combinations of true anesthetics, neuromuscular blockers and tranquilizers.2 Thus, modern chemical immobilization techniques have dramatically reduced the side-effects of drugs and mortalities. Additionally, the use of antagonists to anesthetics is now widely employed, as this avoids the undesirable and potentially harmful effects of drugs and facilitates the speedy of animals’ recovery from chemical immobilization.1,2
Today, the drug formulations available for immobilizing camels 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 camels.
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.
6Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed.
7Nielsen, L. Chemical Immobilization of Wild and Exotic Animals. (1999) Ames, Iowa, Iowa State University Press.
8Lance, W. Exotic Hoof Stock Anesthesia and Analgesia: Best Practices. In: Proceedings, NAVC Conference 2008, pp. 1914-15.
9Ball, L. Camel Anesthesia. Wiley Online Library, 25 July 2014.
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.