Dehydration in Dromedary Camels During Capture and Chemical Immobilization
Camels are even-toed ungulates comprised of two main species: the dromedary camel (Camelus dromedaries, or the Arabian camel) and the Bactrian camel (Camelus bactrianus). The Bactrian camel has two humps and is native to east Asia, while the dromedary camel has a single hump and lives in the warmer areas of the Middle East and northern Africa through northern India.
The ancestors of modern camels evolved in North America during the Palaeogene period and later spread to Asia, subsequently becoming extinct in North America.1 Camels were first domesticated beginning approximately 3,500 years ago. While nearly all camels existing today are domesticated, there are still populations of wild Bactrian camels (C. ferus)in their native range in central China and Mongolia. Dromedary camels have been so widely domesticated that wild dromedary camels are generally understood to be extinct.
Dromedary camels have a long neck, a deep chest and (as mentioned above) a single hump. The hump is composed of fat and fibrous tissue, which allows the camel to store energy when food is scarce.1 As a result, the size of the hump varies based on the camel’s nutritional status, becoming smaller during times of scarce food. The upper lips of dromedary camels are split to allow them to forage for tough, thorny plants.
The dromedary camel has unique adaptations that suit them to living in the desert. A double row of long eyelashes protects their eyes from blowing sand and dust. During sandstorms, they have the ability to close their nostrils to prevent sand from entering the nose and throat.2 They are also able to conserve water in a variety of ways. These camels are able to fluctuate their body temperature throughout the day, which allows them to conserve water by not sweating as the ambient temperature increases.3
In the 1840s, dromedary camels were introduced into Australia to assist in the exploration of the inland continent. Today, there are over one million feral camels in the rangeland ecosystems of Australia. Unfortunately, these animals are causing significant damage to the natural environment. As a control method, radio-collared camels are now being used to enhance population control programs, which involves immobilizing individual camels.4 This procedure carries the risk of giving rise to a variety of complications in the immobilized animals.
Chemical Immobilization and Related Stressors
There are a number of common stressors relating to the chemical immobilization of dromedary camels that can, in some cases, lead to complications during or after an anesthetic event.4,5 The overall health of an individual animal (which might be compromised, and the very reason for its capture) is also a factor affecting the potential for complications during and after anesthesia.
In general, these stressors fall into four categories:
- Physiological: Heavy exercise, hemorrhage, hyperthermia, shock, pain, infection
- Physical: Trauma/surgery, intense heat/cold
- Chemical: Hypoxemia, acid-base imbalance, anesthetic drugs
- Emotional: Anxiety, fear6
Chemical immobilization is represented by the third category. The physical stress of capture and/or attempts to escape during capture on the part of an animal certainly constitute physiological stress; surgical and even environmental conditions can bring about physical stress, and anxiety and fear are nearly always a component to some degree in a capture scenario.
The effects of capture-related stress can include spikes in adrenaline, cortisol levels, heart rate, blood pressure, respiration, metabolic rate, blood glucose, lactic acid and body temperature, while bringing about a decrease in pH and a redistribution of blood within the organs. The effects of capture and anesthesia can activate the fight-or-flight response, HPA-axis activation, hyperthermia, respiratory depression (hypoxemia), lactid acid build-up, acidosis; in severe cases, this can lead to neurological/myocardial dysfunction, multi-organ failure, capture myopathy and death.5,6
While most camels have been acclimatized to human handling and tend to be far less prone to capture-related stress, the possibility of complications arising still exists.
Dehydration in Dromedary Camels
All animals require water to ensure their bodies are working properly. It is so important that essentially all bodily functions require it to remain operative. If an animal loses more water and electrolytes than it is taking in, it will begin to dehydrate and its health will quickly deteriorate.
It is well-known that camels are able to survive without water for long periods compared to other species. The camel's physiological adaptation to the desert environment is due to adaptations that allow minimal use of evaporative cooling, low urinary output and an ability to extract water from undigested feed. Camels can tolerate a loss of water corresponding to 30% of their body weight when dehydrated, whereas other mammals can die from circulatory failure when their water loss exceeds 12% of their body weight.8 The camel’s maintenance of fluid, electrolyte and circulatory homeostasis when dehydrated is believed to be dependent upon hormonal factors. Despite their unique evolutionary adaptations however, dromedary camels can ultimately suffer the ill effects of dehydration.
Since dehydration can lead directly to cardiac arrest, it is potentially a dangerous complication. Electrolytes are minerals that naturally occur in all animals, and they are essential for proper health. Electrolytes are comprised of sodium, chloride, and potassium, and facilitate the movement of nutrients into cells, aid in muscle function, and help regulate nerve activities.5,6 An animal’s natural activities—breathing, urinating, and defecating, as well as simple evaporation—can all cause it to lose fluids. When an animal eats and drinks, the lost water and electrolytes are replaced. If the animal’s fluid intake becomes less than what they are losing and electrolytes are not replaced, dehydration will occur.
Understanding Dehydration in Dromedary Camels
Determining whether or not a state of dehydration exists is based on the distribution of fluid and water in an animal’s body. Total body water (TBW) comprises approximately 60% of an animal’s body weight. Approximately 67% of TBW is found inside the body’s cells; this is referred to as intracellular fluid (ICF). The remaining 33% of TBW is the extracellular fluid (ECF), which comprises:
- Interstitial fluid, which bathes cells and tissues (~24% of TBW)
- Plasma, the liquid portion of blood, which constitutes most of intravascular volume (~8%–10% of TBW)
- Transcellular fluid, which comprises synovial joint fluid, cerebrospinal fluid, bile, and the fluid in the linings of the peritoneal cavity, pericardium, and pleural space (~2% of TBW)5
A simple approximate formula for the distribution of fluids in the body is the 60:40:20 rule: 60% of an animal’s body weight is water, 40% of body weight is ICF, and 20% of body weight is ECF.5,6
Dehydration in dromedary camels can be caused by hyperthermia, chronic vomiting or diarrhea, excessive urination or wound drainage. The stressful nature of capture and chemical immobilization has also been known to bring about dehydration. In both human and veterinary practices, IV fluids are usually administered prophylactically, depending on the nature of the procedure(s). Veterinarians may provide fluid therapy to patients for many reasons, including correction of dehydration, expansion and support of intravascular volume, correction of electrolyte disturbances, and encouragement of appropriate redistribution of fluids that may be in the wrong compartment (e.g., peritoneal effusion).5
Treating Dehydration in Dromedary Camels
During camel anesthesia, monitoring core body temperature is essential,6,9 and intubation is recommended for any anesthetized camel that needs to be transported or anesthetized for greater than twenty minutes.9 immobilization events, an animal’s hydration status can be assessed using various tests. One of the easiest to perform is a skin tent test to check the turgor (moisture level) of the skin. In this test, the skin over the thorax or lumbar region is pulled away from the back. In a well-hydrated animal, the skin immediately returns to its normal resting position. If the tent formed remains standing, it is a likely indication of dehydration. If there is evidence of dehydration in a camel during a procedure, all administration of immobilizing drugs must be immediately suspended. Fluid therapy should begin in the form of lactated Ringer’s solution or 0.9% saline, IV, SQ or IP.5
Perioperative IV fluid therapy is very common in veterinary medicine and allows practitioners to restore intravascular volume, correct dehydration, and administer IV medications quickly.6 While perioperative fluid therapy under many field conditions may be impractical, fluids should always be available in the case of dehydration when chemically immobilizing dromedary camels.
4Laricchiuta P, De Monte V, Campolo M, Grano F, Iarussi F, Crovace A, Staffieri F. Evaluation of a butorphanol, detomidine, and midazolam combination for immobilization of captive Nile lechwe camels (Kobus magaceros). J Wildl Dis. 2012 Jul;48(3):739-46.
5Brivio 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.
6Kreeger T., Arnemo, J., Raath, J. Handbook of Wildlife Chemical Immobilization, International Edition, Wildlife Pharmaceuticals, Inc., Fort Collins, CO. (2002).
8Ali M.A., et. al. Responses to dehydration in the one-humped camel and effects of blocking the renin-angiotensin system. PLoS One. 2012;7(5):e37299. doi: 10.1371/journal.pone.0037299. Epub 2012 May 18. PMID: 22624009; PMCID: PMC3356281.
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