Unpacking alpacas

When a client asked Chris Rayson if he could ultrasound alpacas for pregnancy diagnosis,Rayson had to make a few calls.

ANNE FAWCETT

Rayson, the principal of Ourimbah Veterinary Hospital on the NSW Central Coast, was aware of the growing population of South American camelids in the area.

 In fact, people had begun importing alpacas to Australia in the late 1980s to establish a fibre industry.

The market for alpaca hair in high-end fashion was growing and Australian farmers were keen to cash in. But veterinary knowledge about the exotic creatures was thin on the ground.

“Like most Aussie vets at the time I’d never seen an alpaca,”  Rayson said.

“I rang the company which made the ultrasound machine and asked if it was suitable to use on alpacas. They said yes so off I went.”

Rayson proved a deft hand at performing flank ultrasounds and word got around.

“I became known as the Central Coast alpaca vet.”

Along the way he learned to speak alpaca. Adult males are machos, females are hembras and neonates are crias. There’s also the odd Australian term thrown in: delivering a cria is quaintly referred to as unpacking.

Other vets began talking the same talk and acknowledged the need to pool their knowledge. In 1992  a network, now known as the Australian Veterinary Camelid Association , a special interest group of the AVA was formed.

The AVCA proved a valuable forum, circulating information about dose rates. To date no drugs are registered for use in alpacas so all use is off-label. The association invited overseas speakers from countries with established alpaca industries, particularly Peru and Chile. North American experts shared their knowledge about llamas.

“Llama medicine is nearly identical to alpaca medicine.”

It was a steep learning curve. Of the common veterinary species alpacas most resemble small ruminants, “although they don’t exactly fit into that category”  Rayson said.

Alpacas require a different set of handling skills. Most alpacas will stand for examination if cradled firmly around the neck, as pictured. But others, notably pregnant females, vocalise and spit no matter what form of restraint is employed.

“Spitting is a defence mechanism they use and they’re very accurate. It’s actually stomach contents, it has a foul smell and sticks to you for days.”

Rayson quickly learned to avoid making direct eye contact, a gesture to which most alpacas will respond by spitting copious volumes of whatever it is. Just one of their many charming idiosyncracies.

Alpacas, like other camelids, have a three-compartment stomach. Instead of ovulation cycles they have follicular waves. They are induced ovulators and can be mated at almost any time of the year. And they have diffuse placentation, similar to horses. Their erythrocytes are elliptical, which is thought to be an adaptation to high altitude living.

“They get some of the same diseases that ruminants get, like the clostridial diseases, especially enterotoxaemia (pulpy kidney), pneumonias and neonatal scours.”

Rayson said alpacas are particularly prone to liver disease. “Some people call them hepatic wimps.”

Their livers certainly do not tolerate sporidesmin, a toxin produced by the fungus Pythomyces chartarum. It is the same toxin responsible for facial eczema in sheep, a big problem in New Zealand. In sheep photosensitisation is secondary to liver damage, but alpacas commonly die due to massive liver necrosis before skin lesions appear.

The fungus flourishes on dead plant material, particularly in humid conditions.

“Outbreaks typically occur in late summer after people slash paddocks and leave the grass to mulch.”

One client lost 12 breeding animals in an outbreak. “That was early on when breeding animals were worth about $20,000 a head so it was a huge loss.”

Diagnosis is typically based on post mortem examination and histopathology. The characteristic lesion is bile duct proliferation. An alternative is a spore count, as the fungus produces a characteristic spore.

Grass samples are taken and mixed with detergent and water. A spore count is performed on the supernatant.

“The safest way to avoid sporidesmin toxicity is to keep the pastures short. Alpacas are selective grazers and will pick through long grass looking for tender shoots. This is where they tend to pick up dead plant material.”

If paddocks are slashed cuttings should be removed as soon as possible.

Rye grass staggers is another common pasture based problem.

Parasitic disease is also common, with the barbers pole worm (Haemonchus contortus) the biggest offender by far in the Central Coast region.

“We’ve seen cases of extreme anaemia, its common to get a PCV of less than 10 in an animal that doesn’t look sick. The lowest PCV I’ve seen in a live alpaca was six.”

Rayson has performed blood transfusions on valuable crias but said those animals often do poorly in the long term.

Alpacas are also susceptible to Ixodes holocyclus, the paralysis tick. They respond well to the canine antiserum.

“We pre-medicate with an antihistamine and give the antiserum slowly but they tolerate it well. We’ve only had one possible anaphylactic reaction over the years.”

These days Rayson finds himself treating alpacas regularly. As the Australian industry has flourished the price of alpacas has dropped, allowing more people to keep them as pets.

“They do not need a large area, they are not difficult to look after and they make just as good pets as goats do,” Rayson said. They can be trained to walk on a halter.

Aside from routine procedures like wethering and tooth trimming, Rayson deals with the odd disease outbreak or less common health problem. He recently removed a fibrosarcoma from the forelimb of a stud male under general anaesthetic.

Rayson says that Australian vets are in good position to provide quality service to alpaca-owning clients.

“I think this is a good example of what Tom Hungerford used to call the ‘goanna track to success.’,”  Rayson said. “A chance encounter with alpacas led to a development of knowledge, partly from personal experience, partly from talking to colleagues. Alpaca vets in Australia are probably as knowledgeable and as skilled as any alpaca vets in the world – and that’s all happened in the space of 10 or 12 years.”