Risk of Infection on Pasture Often Overlooked

There is growing demand for improved animal welfare, opportunities for natural behaviour, and food production that is more closely connected to the natural environment. But how well is disease prevention adapted to these farming systems?

This was one of the key questions addressed by the researchers. The study covered European countries, including Norway, as well as non-EU countries with comparable outdoor livestock production systems. The findings suggest that current biosecurity assessments in livestock production have largely been developed for animals housed indoors. As a result, important risk factors associated with grazing animals and outdoor access may be overlooked.

Researchers Identified Major Gaps

The researchers reviewed 71 scientific studies assessing biosecurity on farms with outdoor pigs, cattle, sheep and other ruminants. The aim was to identify which elements and measures are included when biosecurity is evaluated.

The review showed that certain measures designed to prevent disease introduction are almost always included. These include fencing, visitor controls, quarantine of newly purchased animals, testing before introduction, and the management of dead animals. At the same time, the researchers found that biosecurity assessments tend to focus more on how diseases enter a herd than on how they spread within it.

The study also revealed that biosecurity measures relating to outdoor areas and outdoor access receive considerably less attention.

Pastures Are a “Blind Spot”

Fewer than one in ten studies assessed biosecurity measures directly related to soil, pastures and other outdoor environments. The use of vehicles in outdoor areas was also rarely examined.

“This is surprising, as much of the interaction between animals, people, equipment and the environment take place outdoors in these production systems. Pastures and outdoor areas can play an important role in the survival and spread of infectious agents,” says Siv Meling, a researcher in livestock and wildlife health at the Norwegian Veterinary Institute and subject matter expert in biosecurity.

She was one of the researchers involved in this EUP AH&W project (European Partnership on Animal Health and Welfare).

Wildlife Receives Too Little Attention

Another important finding was that contact between livestock and wildlife often receives limited consideration.

Wild boar can spread African swine fever. Deer species and badgers may contribute to the spread of bovine tuberculosis. Birds can carry a range of infectious agents.

Nevertheless, the review found that most questions relating to wildlife contact were considered in fewer than 30 per cent of the studies.

“This may be problematic because animals with outdoor access often have a greater likelihood of contact with wildlife than animals kept indoors,” says Meling.

Difficult to Compare Studies

The study also revealed considerable variation in the methods used to assess biosecurity measures.

Some assessments were designed to identify risk factors for specific infectious agents, while others focused on overall on-farm biosecurity. When the objective was to investigate a single disease, certain biosecurity elements were far more likely to be omitted.

According to Meling, this makes it difficult to compare results across studies, production systems and countries.

Important for Animals, Farmers and Authorities

The findings have implications well beyond the research community. If biosecurity assessments fail to capture key risk factors in outdoor production systems, producers, veterinarians and authorities may underestimate important routes of disease transmission.

At the same time, the researchers emphasise that outdoor access offers many benefits. Animals have greater opportunities to express natural behaviours, enjoy increased freedom of movement, and experience a more stimulating environment. The objective is therefore not to move animals indoors, but to develop biosecurity protocols that better suit the challenges associated with outdoor farming systems.

Animals with Outdoor Access Need Tailored Biosecurity

The study highlights a clear need to rethink biosecurity in livestock systems that provide access to outdoor areas. Today's assessments often focus on housing facilities, fencing and visitor controls, while less emphasis is placed on conditions in pastures, the use of outdoor spaces, and contact with wildlife.

To strengthen animal health and improve preparedness for future disease outbreaks, the researchers suggest that these factors should be more fully incorporated into future biosecurity assessments. In short, pastures and the environment surrounding livestock deserve far greater attention than they currently receive.

Read the full study: Review of biosecurity parameters included in assessments of pig and ruminant farming systems with outdoor access - (ScienceDirect).

Funding: This work was co-funded by the EU project EUP AH&W (European Partnership Animal health and Welfare) (Grant Agreement No. 101136346) under the Horizon Europe programme.