Bloat in Alpaca During Capture and Chemical Immobilization
Alpacas (Vicugña pacos) are slender-bodied animals with a long neck and long legs, a short tail, a small head, and large, tapering ears. Alpacas are members of the camelid family (Camelidae), which includes dromedary camels, Bactrian camels, wild Bactrian camels, llamas, alpacas, vicuñas, and guanacos.1 South American camelids are also referred to as lamoids.
Alpacas are pseudo-ruminants, which means that they possess a single stomach divided into three compartments instead of four, like other ruminants. They are the most limited in range and the most specialized of the four species of lamoids, being adapted to the altitudes from 13,000 to 15,700 feet across Chile, Peru, and Bolivia. Remains of alpaca found at elevations closer to sea levels suggest that alpaca may once have had a wider geographical distribution, and that their range was reduced with the arrival of the Spanish conquistadores and their introduced livestock.2
Alpacas are the smallest of the domesticated lamoids. The weight of an adult alpaca ranges from 120 to 140 lbs, with a height ranging from 2 to 3 feet. There are two breeds of alpaca, known as huacaya and suri, although they are officially one species. The suri alpaca has a fleece with long, thick locks which hang loose and long. Huacaya alpacas have a coat which is shorter and denser. Over 90% of alpacas are huacaya. Their coats vary in color from black or brown to pale yellow and white.
Interestingly, alpacas and llamas are able to breed with one another and produce fertile offspring. This suggested that both species may have stemmed from guanacos, the parent species of the llama. However, genetic studies later concluded that alpacas are more likely the domesticated descendants of vicuñas, and that this occurred between 6,000 and 7,000 years ago.3
One of the most interesting things about the alpaca is that they appear to be comfortable in just about any climate. Alpaca wool fibers are hollow, which makes them able to insulate very well, to absorb moisture and wick it away. As a result, alpaca farming has become a worldwide cottage industry. Alpacas have been domesticated for thousands of years; it is thought even prior to the Incas, who raised and bred alpacas for wool clothing that was reserved for royalty.
Alpacas and Chemical Immobilization
Alpaca management, research and farming often require the chemical immobilization of these animals. Unfortunately, this can lead to a variety of capture‐induced risks while immobilized.4 Since all sedative and anesthetic drugs have a certain level of toxicity, the use of these drugs invariably carries a risk, even to the life of healthy animals. General anesthesia techniques for camelids are similar to those for ruminants and horses.1,2
Monitoring core body temperature is essential in alpaca 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 alpacas 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 alpacas be orotracheally intubated for procedures lasting more than 20 minutes.7
Bloat in Alpaca and How it Occurs
Bloat is a serious condition that can be fatal if 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 is a condition that has been reported in alpaca; it has been known to occur spontaneously, but is most closely associated with capture and chemical immobilization events.
Since alpacas are ruminants, an extended 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.
In instances of bloat, the life-threatening aspects arise from the twisting and flipping of the stomach. When an alpaca’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 bloat progresses, the stomach expands. As this occurs, 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. Alpaca 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 alpaca, 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 (e.g., xylazine), which can result in a ruminal atony and subsequently, bloat.3
Resolving Bloat in Alpaca
If an immobilized alpaca 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.4-7
If available, 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 an alpaca’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. 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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