Bloat in Dromedary Camels During Capture and Chemical Immobilization

Once called “the ships of the desert,” dromedary camels (Camelus dromedaries) were domesticated more than 3,000 years ago. Today, humans still depend on them for transport and for their wool, milk, meat, leather and dung (which can be used for fuel).^1,2 The dromedary camel (also known as the Arabian camel) exists today only in a domesticated form, and about 90% of the world’s camels are dromedary camels.

The dromedary camel occupies the arid regions of the Middle East and northern Africa through northern India. There are also feral populations in central Australia, where they were introduced in the middle of the 19^th Century. The dromedary camel has one hump, and the Bactrian camel (Camelus bactrianus), which lives in the Gobi Desert in China and the Bactrian steppes of Mongolia, has two. A camel’s humps store fat, which they use as energy when food is scarce.

Dromedary camels can travel as fast as horses, and can also endure extremely long periods of time without food or water. They can easily carry 200 pounds while walking 20 or more miles a day in the desert. They 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

Male dromedary camels weigh in at approximately 900 to 1,400 pounds; females are about 10% smaller and lighter. Their color is light brown to medium gray. 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

The Chemical Immobilization of Dromedary Camels

The management of and research involving dromedary camels often requires the chemical immobilization of these animals. Unfortunately, this can lead to a variety of capture‐induced risks while they are immobilized.⁴ Anesthetic drugs are never completely devoid of toxicity, so the induction of anesthesia 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.^2,3

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

As mentioned earlier, dromedary camels were first introduced into Australia in the 1840s to assist in the exploration of inland Australia. This has resulted in over one million feral camels currently occupying the rangeland ecosystems of Australia. Unfortunately, these animals are causing significant damage to the natural environment. Today, radio-collared camels are being used to enhance population control programs.⁷ The procedures involved in placing the radio collars necessitate the chemical immobilization of these animals, which carries the risk of complications such as bloat.

Bloat and How it Occurs

Bloat in dromedary camels involves an overdistention of the rumenoreticulum with the gases of fermentation. This can occur in the form of a persistent foam mixed with the ruminal contents (primary or frothy bloat) or in the form of free gas separated from the ingesta, (secondary or free-gas bloat).⁴ Since camels are ruminants, a prolonged period of time without movement can result in a buildup of gas within the digestive tract. Failure to eliminate this gas can result in secondary bloat and distension or bloating of the rumen. This can compress other surrounding organs and obstruct blood flow.

Bloat has been reported in dromedary camels; it has been known to occur spontaneously, but is most closely associated with capture and chemical immobilization events. In instances of bloat, the life-threatening aspects arise when the stomach twists or flips. When a 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. Camels 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.

Xylazine was probably 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 Dromedary Camels

In camel sedation and anesthesia, positioning is important to reduce the likelihood of complications such as regurgitation, aspiration and bloat. It is recommended that the animal’s head is kept elevated above the stomach; it should not be rolled dorsally unless an endotracheal tube has been placed.

If an immobilized camel starts to bloat, all administration of immobilizing drugs should be suspended. The animal should be positioned (or re-positioned) into sternal recumbency with the neck extended and the head with the nose pointing down. Intubation of the animal to relieve gases 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 immobilizing agents, which may include respiratory depression and cardiovascular issues. 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.⁵

In the event of a camel’s death from bloat, post-mortem gas formation in the alimentary tract should be distinguished from ante-mortem bloating, which itself can be a cause of death. In the latter case, there may be signs of asphyxiation.^4,6