Bloat in Bactrian Camels During Capture and Chemical Immobilization

Native to the steppes of Central Asia, the Bactrian camel (Camelus bactrianus) is a migratory species, with habitats that range from rocky foothills to deserts. These are regions with extremely harsh conditions in both summer and winter. Here, vegetation tends to be sparse and water sources are often limited.

The Bactrian camel differs most conspicuously from the dromedary camel (Camelus dromedaries, which is native to the Middle East and western Asia) in that they have two humps on their backs instead of one. These humps are composed of fat, which the camels use to store energy when food is scarce.

Bactrian camels have long, wooly coats which vary in color from beige to dark brown. They have a mane and beard of long hair on the neck and throat. Like the dromedary camel, Bactrian camels have a split upper lip, which allows them to effectively forage for short plants in areas of sparse vegetation. They have long eyelashes and nostrils that they can close, which help to keep out dust from sandstorms which occur in their natural range.²

Bactrian camels are diurnal, sleeping at night and foraging for food during the day. Technically, they are omnivores, but are primarily herbivorous. When well-fed, the camel’s humps are erect, but as food sources decline, they shrink and tend to lean over. They can go without water for months at a time, but when water is available, they can drink up to 30 gallons at a time.

Often, large groups of Bactrian camels will congregate near rivers after rain or at the foot of the mountains, where water can be obtained from springs in the summer months, as well as from melting snows during the winter.¹ Temperatures in the Bactrian camel’s natural environment range from as low as −40 °C in winter to 40 °C in summer.

Bactrian camels are polygynous animals, with one male mating with multiple females. During mating time, the males can be violent and may bite, spit or sit on other males.³ Gestation lasts from 12 to 13 months, after which one or two calves will be born. The calves are born precocial and are able to stand and run shortly after birth.³ The young are nursed for about 18 months and stay with their mother for 3 to 5 years.

Bactrian Camels and Chemical Immobilization

The management of and research involving Bactrian camels often require chemical immobilization. Unfortunately, this can lead to a variety of capture‐induced risks.⁴ Anesthetic drugs are never completely devoid of toxicity, thus 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 easily employed in order to provide immobility and analgesia.

General anesthesia techniques for camels are similar to those for ruminants and horses.^1,2 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

Recommendations for preparing Bactrian 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.³Withholding 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.⁷

Bloat in Bactrian Camels

Bloat is a serious condition that can prove fatal if left untreated. In small animal veterinary practices, it is often seen in large dogs and is known as gastric dilatation-volvulus (GDV), which can occur spontaneously. Bloat occurs when an animal's stomach fills with gas, food, or fluid and subsequently twists. Bloat has been reported in camels; while it has been known to occur spontaneously, but is most closely associated with capture and chemical immobilization.

Because 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 bloat and distension or bloating of the rumen. This can compress other surrounding organs and obstruct blood flow.

The Dynamics of Bloat

When bloat occurs, the life-threatening aspects arise from the twisting and flipping of the stomach. 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 twisting aspect is more severe, as it completely obstructs the blood supply to major organs and can impact blood flow throughout the whole body, resulting in shock.⁴

As the bloated stomach expands, it exerts pressure on the large abdominal arteries and veins. The stomach’s blood supply is cut off; subsequently, toxic products build up and tissues begin to die. A camel can go into shock very quickly, and extended periods without treatment increase the risk of further damage and even death.^4,5

A sternal recumbency position is vital when performing procedures in chemically-immobilized camels, 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 give rise to a ruminal atony and subsequently, bloat.³ Xylazine, an α-2-agonist, is used in many species; it 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.^4-6

Resolving Bloat in Bactrian Camels

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 may be performed; in some cases, trocharization of the rumen may be necessary.⁵ If the veterinarian has high confidence that the bloat has been caused by 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 to race at a rate sufficient to cause heart failure. Medication for shock and electrolyte administration are 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, signs of asphyxiation are likely to be present.^4,6