Bloat in Camels During Capture and Chemical Immobilization
Camels include any of three species of large hoofed ruminants that inhabit northern Africa and Asia 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.1
Camels are native to northern Africa and southwestern Asia, and were introduced into Australia during the 19th Century. Bactrian camels are native to the Gobi Desert in China and the Bactrian 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.).2 Camels have long been used by humans for their wool, milk, meat and leather.3
Camels have an unmistakable and iconic appearance, with their humped back, short tail, long legs, and a long neck. 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.2
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.3
Camels can last for several months without food, and they can go a week or more without water. Their back humps store up to 80 pounds of fat, which they break down into energy when food is not available.2,3 The humps give camels their ability to travel in the desert without water. When camels do drink, they can consume 30 gallons of water 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.1
Camels and Chemical Immobilization
Camel management and research often requires chemical immobilization. Unfortunately, this can lead to a variety of capture‐induced risks while immobilized.4 Since anesthetic drugs are never completely devoid of toxicity, the induction of anesthesia invariably carries a risk even to the life of healthy animals. Despite their size, camelids (camels, llamas and alpacas) are often agreeable when it comes to handling, thus sedatives and anesthetics are used to provide immobility and analgesia. General anesthesia techniques are similar to those for ruminants and horses.1,2
Monitoring core body temperature is essential in camel anesthesia.4 Until the more recent use of formulated drugs (e.g., combinations of α2-agonists such as medetomidine, detomidine, xylazine and their reversal agents), opioids were the mainstay of anesthesia in wildlife and captive care.5
Guidelines for the preparation of camels for anesthesia and surgery include decreasing the size and pressure in C1 before anesthesia, withholding food for 12 to 18 hours in adults and withholding water for up to 12 hours.3 Withholding food or water in neonates is not recommended, as this increases the risk of dehydration and hypoglycemia. It is also recommended that camels be orotracheally intubated for procedures lasting more than 20 minutes.8
Dromedary camels were first introduced into Australia in the 1840's to assist in the exploration of inland Australia. Today, there are over one million feral camels in the rangeland ecosystems of Australia.7 Unfortunately, these animals are causing significant damage to the natural environment.
As a control method, radio-collared camels are being used to enhance population control programs. This involves immobilizing individual camels, attaching a telemetry collar, and releasing the collared animal to re-join its herd. The collared individuals are subsequently tracked via GPS and communications satellites.7
Bloat in Camels as a Complication
Bloat is a serious condition that is fatal if left untreated. It is often seen in large dogs in small animal veterinary practices and is known as gastric dilatation-volvulus (GDV), and can occur spontaneously. Bloat occurs when an animal's stomach fills with gas, food, or fluid and subsequently twists. Bloat is a condition that has been reported in camels; it has been known to occur spontaneously, but is most closely associated with capture and chemical immobilization events.
Since camels are ruminants, a prolonged period of time without movement can result in a build up of gas within the digestive tract. Failure to eliminate this gas can result in bloat and distension or bloating of the rumen. This can compress other surrounding organs and obstruct blood flow.
How Bloat Occurs
In instances of bloat, life-threatening aspects arise from the twisting and flipping of the stomach. When the camel’s stomach becomes severely distended with gas, fluid or food, it puts pressure on the surrounding organs and decreases blood flow to and from these organs. The twisted stomach is more severe, as it completely obstructs blood supply to major organs and can impact blood flow throughout the whole body, resulting in shock.4
As the stomach expands, it exerts pressure on the large abdominal arteries and veins. The blood supply is cut off to the stomach; subsequently, toxic products build up and tissues begin to die. Camel (or any other animal experiencing bloat) can go into shock very quickly, and extended periods without treatment increase the risk of further damage and death.4,5
When performing procedures in chemically-immobilized camel, a sternal recumbency position is vital whenever possible, as bloat can more readily occur with animals in lateral recumbency. Other causes of bloat include the use of immobilization drugs such as the α-2-agonists, which can result in a ruminal atony and subsequently, bloat.3
It is likely that xylazine was the first α-2-agonist to be used in veterinary medicine. It is used in many species, is easily available and inexpensive. It promotes good muscle relaxation, sedation and a short period of analgesia. It can, however, cause hyper salivation, muscle tremors in some species and GIT motility suppression. The latter can give rise to ruminal atony and bloat.4-6
Resolving Bloat in Camel
If an immobilized camel starts to bloat, all administration of immobilizing drugs should be suspended. The animal should be re-positioned into sternal recumbency with the neck extended and the head with the nose pointing down. Intubation of the animal to relieve gases inside may be done; in some cases, trocharization of the rumen is recommended.5 If the veterinarian has high confidence that the bloat is being caused by the anesthetic agents, he or she may employ the available reversal agents to antagonize their effect.4,6
Reversal drugs (e.g., diprenorphine, naltrexone, naloxone) should be given as quickly as possible to avoid the side effects of the immobilizing agents, which may include respiratory depression and cardiovascular issues, among others. Intravenous catheters should be placed and fluid therapy begun, as bloat can cause the heart rate to race at a rate sufficient to cause heart failure. Medication for shock and electrolytes are all essential in stabilizing the animal. Premature ventricular contraction (PVC) is often associated with bloat. If this arises, intravenous medications will also be needed to stabilize the heart rhythm. If the disturbed heart rhythm is noted early on, the animal’s prognosis for recovery is generally good.5
In the event of a camel’s death from bloat, post-mortem gas formation in the alimentary tract, especially in ruminants, should be distinguished from ante-mortem bloating, which itself can be a cause of death. In the latter case, there are likely to be signs of asphyxiation.4,6
4Wolfe, B. (2015). Bovidae (except sheep and goats) and antilocapridae. In Miller, R. E., Fowler, M. E. (eds) Zoo and Wild Animal Medicine. (Volume 8). St Louis, Missouri: Elsevier Saunders, 626-644.
5Lance, W. Exotic Hoof Stock Anesthesia and Analgesia: Best Practices. In: Proceedings, NAVC Conference 2008, pp. 1914-15.
6Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed. Sunquest Publishing, 2007, 432 pages.
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.
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