Dehydration in Alpacas During Capture and Chemical Immobilization

The alpaca (Vicugña pacos) is a lamoid, a word used to reference several species of South American camelids (Camelidae). This particular group of animals includes llamas, alpacas, vicuñas, and guanacos. While camels, llamas, and alpacas have been domesticated for thousands of years, undomesticated guanacos and vicunas still roam freely in herds in the mountains of Chile, Peru, and Bolivia. Like camels, lamoids are believed to have originated in North America over 40 million years ago, with lamoids migrating to South America and camels migrating east via the Bering Strait and later becoming extinct in North America.¹

Alpacas are slender-bodied animals with a long neck and long legs, a short tail, a small head, and large, tapering ears. They are the most limited in range and the most specialized of the four species of lamoids, being adapted to altitudes from 13,000 to 15,500 feet.² They are distinguished from llamas (the largest South American camelids) by their smaller size, and they 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.

The disposition of alpacas is generally friendly and gentle. In the Andes, the mating period for alpacas runs from August through September. Their babies are called crias, which typically weigh 15-20 pounds at birth. Adult alpaca reach about 3 feet in height and 150 pounds in weight.² Alpacas live 15 to 25 years.

Lamoids vary by size and purpose, with some (such as llamas) being used as pack animals and others (such as alpacas) being valued for their fleece.¹ The alpaca encompasses two breed types: the huacaya and the suri. Huacayas are the more common type, and account for about 90% of all alpacas.² The two breed types differ primarily in terms of the properties of their fleece. Alpacas are the most widely-used lamoids for fleece production.

The fleece of the alpaca is lightweight, strong, high in insulation value and very resistant to moisture. It has been reported that during the height of the Incan civilization, the wearing of robes made of alpaca fleece was reserved for the nobility and royalty.³ Alpaca wool fibers are hollow, which gives them the ability to insulate very well, and to absorb moisture. As a result, alpaca farming has become a worldwide industry.

Alpacas are pseudo-ruminants, possessing a single stomach divided into three compartments (instead of four, like other ruminants). They produce rumen, chew cud and are able to process food very efficiently. In the field, alpacas graze on grasses and plants. On farms, alpacas will eat grass or hay. They consume approximately two pounds per 125 pounds of body weight daily in hay or fresh pasture. Some farmers feed extra alfalfa to alpacas that are leaner, or those which live in very cold temperatures.³

Alpacas and Chemical Immobilization

Research, medical examination, sample collection and animal identification sometimes requires the chemical immobilization of alpacas. Research in this area has revealed that the physiological and behavioral effects of capture—regardless of the method—can be as important as the direct risks of injury or death of an animal.^4,5

There are a number of common stressors involved in the chemical immobilization of alpacas that can lead to complications during or after an anesthetic event. The overall health of an individual animal (which might be poor, and in some cases the very reason for its capture) is also a factor affecting the potential for complications during and after anesthesia.

These stressors—stimuli or stress-inducing agents—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 agents are represented by the third category, although elements of the other three may be included in immobilization events. 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.

Even though alpacas are largely domesticated, the effects of acute stress during capture 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

Dehydration in Alpacas

Animals require water to ensure that their bodies continue to work properly. It is so important that 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. 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 While dehydration may seem like a minor concern compared to some surgical complications, inasmuch as it can lead directly to cardiac arrest, dehydration is potentially quite dangerous.

An animal’s natural biological functions—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, dehydration will occur.

Understanding Dehydration in Alpacas

The dynamics of dehydration lie in the distribution of fluid and water in the 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

An 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 alpacas can be caused by hyperthermia, chronic vomiting or diarrhea, excessive urination or wound drainage. In both human and veterinary practices, IV fluids are usually administered prophylactically, depending on the nature of the procedure. Veterinarians often 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 Alpacas

Monitoring core body temperature is essential in camelid anesthesia,⁶ and intubation has been widely recommended for any anesthetized alpaca that needs to be transported or anesthetized for greater than twenty minutes.⁷ During immobilization events, 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. To perform 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 an alpaca 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

In veterinary medicine, perioperative IV fluid therapy is very common; this 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 alpacas.