Designated pathogen-free pigs – origins and welfare

Origins of LCT’s pigs

The rugged and windswept subantarctic Auckland Islands (about 465 km south of Bluff, New Zealand) are home to a unique breed of disease-free pigs. These pigs are the descendants of pigs left by sailors in the early 1800s as a food source in case of shipwrecks.

In 1997, the Rare Breeds Conservation Society brought 17 pigs from the Auckland Islands to Invercargill. The pigs were housed in a special ‘clean’ facility where they thrived and bred successfully. The Department of Conservation is eventually planning to eradicate pigs from the islands because they are destroying rare plant life and threatening bird populations.

Pathogen-free pigs supply cells for transplants

LCT tested the relocated Auckland Island pigs and found that they were free of diseases commonly found in domestic pig herds. Their prolonged isolation on the island had minimised their exposure to disease-causing pathogens, like viruses and bacteria. These pigs are the ideal source of cells for transplanting into people – as long as they remain pathogen-free. Find out more about Pig viruses and virus testing in this article.

Keeping pigs pathogen-free

The pigs are housed in a purpose-built designated pathogen-free (DPF) facility that is designed to protect the pigs from exposure to infectious diseases. The facility is made of concrete – a robust material that pigs cannot damage and is easy to clean. It is a windowless building with controlled temperature and lighting. The air in the facility is pumped in so the highest-pressure area is where the pigs are kept and the pressure drops as you get closer to the facility entrance. This helps to prevent pathogens getting in.

A barrier to pathogen entry

Importantly, the DPF facility contains a physical barrier through which only clean and sterilised materials can pass. Every item that crosses the barrier into the pig area is filtered or sterilised to kill pathogens – this includes air, water, feed, bedding, tools and environmental enrichment toys. Even staff must shower and change into clean clothes, boots, hats, gloves and masks before they can cross the barrier and start work. Staff don’t work if they are ill or have been in contact with someone with an infection, such as a cold, sore throat, flu or measles. Also, the facility staff don’t have contact with any pigs outside the facility.

Pig welfare and environmental enrichment

Like all other animals in New Zealand, the pigs at LCT are kept according to the Animal Welfare Act 1999. An animal ethics committee oversees LCT’s research. Pig welfare is important to the staff at LCT, and they are constantly striving to improve their processes.

All staff in the DPF facility are trained to work with pigs in a calm, quiet manner. To maintain their pathogen-free status, the pigs are kept inside the facility at all times, so it’s important to allow them to move freely. They are kept in large, individual pens but can see their neighbours and are allowed to socialise twice a day when their pens are cleaned. Environmental enrichment toys are used to entertain and distract the pigs. Pigs are playful and like toys such as basketballs, shipping buoys and pull-toys.

Pig maternity facilities

Ultimately, LCT pigs are kept so that they breed and produce piglets that are used as a source of cells for transplants. The DPF facility has a maternity room for pregnant sows close to giving birth, which has underfloor heating and dim lighting. Each sow has 2–3 litters of piglets each year. Once the piglets are 7–16 days old, they are usually removed from the sows. The piglets are then transported to LCT where the cells are harvested and they are euthanised. Sows may get upset when their piglets are removed, and staff use a number of techniques to distract the pigs at this time such as moving them to new pens and giving them new toys to play with.