The fact that 50 percent of the world’s pig population are in non-intensive production systems, poses a potential threat to global pig health—new investment is needed to modernize the industry and reduce disease risks. That was the message of pig health expert, Dr Dan Tucker, who delivered the Tom Alexander Memorial Lecture at the 22nd International Pig Veterinary Society in Jeju, Korea, in June. 

 Preventing pig disease 

Calling for international cooperation and communication to help pig producers make the necessary changes and increase surveillance, Dr Tucker, a lecturer in pig health at the University of Cambridge in the UK, also urged governments to help local pig farmers invest in what could be “quite expensive” alterations to improve production and produce healthy pigs.

“There are some 900 million pigs in the world, with about 50 percent produced under intensive production systems,” said Dr Tucker. “But the other half are in non-intensive systems, such as backyard pig farms, particularly in developing countries such as Vietnam, Cambodia and parts of China and they need time to change.”

The problem is that while intensive systems include regular up-to-date disease and pathogen monitoring, there is little or no monitoring in the non-intensive systems, which can lead to a high risk of new diseases emerging, he explained.

“Moreover, these non-intensive production pigs have a greater chance of contact with wild animals and other domesticated species and catching some new disease, or pathogen from them,” said Dr Tucker. “If these new pathogens mutate in the pig, they could jump from pigs in the non-intensive systems to others in intensive systems.”

This is important because he said he believes that more focus on pig health can help producers improve productivity and meat safety, as well as provide better pig welfare on farms.

 Biosecurity measures 

“To control and prevent disease, everything has to be based on evidence, which has to come from surveillance,” Dr Tucker explained. “If people can’t keep a proper watch over half of the world’s pig population, they have to be prepared for some surprises. 

“That’s why I see the fact that 50 percent of our pigs are still in non-intensive systems is a major potential threat to global pig health,” he said.


“Global organizations such as FAO and WHO could help build technical partnerships to facilitate change by helping developed countries transfer knowledge and expertise in endemic diseases, diagnostic testing, sample collection and surveillance to reduce the health risks,” says Dr Tucker. “They could also become important sources of funding to promote collaboration between nations.”

“Global pig diseases don’t respect borders and we need strict international trade regulations,” says Dr Tucker. “Importers should be required to test pork in advance and evaluate the health status of pigs shipping products to help us find out how pathogens move around. Can they only survive within live pigs and how to these viruses move from one country to another? We need surveillance work at all levels from the farm and the regions, as well as national and international data collection so we can see how they move and then take action to control them.”

Health vs. health status

When asked what he thought pig producers should be doing, Dr Tucker said: “Firstly, they need to understand the difference between ‘health’ and ‘health status’.”


He explained: “A pig that carries known pathogens, but thanks to a good environment and management remains free from clinical signs of disease is ‘healthy’, even though it has a low ‘health status’. However, the same pig will quickly become sick from these pathogens if the environment or management is less than ideal. Furthermore, a pig that lives on a farm with a high health status (such as a PRRRS-free herd) can still have a low health if there are failings in environment and management; this is because ubiquitous organisms such as Clostridia or E. coli (present in all environment and all pigs) take the opportunity to cause disease."


In other words, good environment and good management are critical factors to maintain good pig health.

“Producers with pigs in intensive production should also pay attention to the anti-microbial issues, as well as the continuing problems caused by PRRS, hesaid.  "They must learn to use antibiotics more responsibly and to reduce their dependence on them by using better diagnosis tests, sensitivity testing and preventative measures to improve pig health. While it is not possible to stop using antibiotics completely, we must use them properly – and we need to collect more evidence regarding antimicrobial resistance in humans and animals. We have to accept that this is a joint responsibility, because there may be other sources of antimicrobial resistance, such as plant production, or fisheries and so forth.”

Dr Tucker thought it was especially important for the manufacturers and retailers of these drugs to take more responsibility for ensuring their products were used properly when treating sick animals.

He also believes that the application of new technologies could play a critical role in combating disease threats and helping to maintain happy, healthy pigs by using whole genome sequences to research bacterial respiratory diseases and related organisms. 

Some researchers had already started to identify the differences between disease-related strains of streptococcus suis and non-disease-related colonised strains, translating to new diagnostic tools and methods to track bacteria as they moved from the sow to the piglet and through to the finishing stages, Dr Tucker said.

“This technique could help us discover at what stage of life pigs are most susceptible to infections, which would help us set up better control programs and design new methods to help make the industry less reliant on antibiotics,” he said.