Portrait of a man (phd-student Lex Roelofs) in the laboratory dressed in lab gown holding a petri dish.
Photo: Lisa Chröisty, SLU

Happy feet: Better animal welfare for cows and increased food production combined

News published:  30/06/2025

Animal welfare is on the agenda: cows included. But when increasingly more farmers are changing the way their animals are held one disease in particular has escalated - a cocktail of bacteria that spreads rapidly and at ground level, between the hooves. And the big challenge is detecting it in time.

On the bench are test tubes with blood and milk samples from cows. The laboratory lamp casts a sterile light over the room. When the liquid from a pipette is dropped into the test template, the sample board lights up and reports the results.

Infected. Not infected. Infected. Not infected.

A taste of the future.

Picture of hands working with equipment in the laboratory.
Photo: Lisa Chröisty, SLU

A cocktail of bacteria

Is it possible to improve both animal welfare and food production through new discoveries in the lab? The answer is yes, and in this case it's something as simple as finding better ways to quickly and easily detect bacterial diseases, because animal welfare actually affects how well they produce food too.

But let's take it from the beginning. What is this bacterial cocktail that is being talked about?

Digital dermatitis, a hoof disease that is both painful, contagious and very common among cows on both dairy and beef farms. Today, diagnosis requires a visit to a veterinarian or hoof specialist, a complicated process that often misses cases in their early stages.

This is a pity, as it means that the infection often spreads further and the problems continue, says Lex Roelofs, PhD-student in the project.

The disease is multibacterial, which means that it consists of a combination of many different types of invading bacteria.

Simply like a cocktail of bacteria, Lex Roelofs continues.

But why has this become so topical now? Well - contradictorily, because of improvements in animal welfare.

The impact of better animal welfare regulation: positive and problematic

The regulatory framework for farm animals has been developed in recent years to improve the welfare of cows, among other things. One major change is that cows are no longer tied up in stalls but are now free to roam in groups, in a kind of loose housing indoors. In addition to the positive effects, this has proved to pose new challenges.

Because this disease is transmitted via the cows' hooves (feet), the infection spreads quickly even to healthy animals by moving on the same surface that an infected cow previously walked on, says Lex Roelofs.

More than half of Swedish farms with cows are estimated to have the disease in a number of their animals, and both meat and dairy animals are affected. The disease is found all over the world, and internationally the number of affected farms is in some places even higher than in Sweden. These statistics have become increasingly worse in recent years, indicating a trend that does not seem to be resolving itself.

The changes in the way we keep farm animals are therefore GOOD changes, but we need to find ways to detect infected animals more quickly and prevent the spread of this disease,” says Lex Roelofs and continues: And for that to happen, it needs to be easier to detect the disease, even at an early stage.

Internationally, attempts have been made to mass treat cows by footbathing, so as not to risk missing any infected individual. However, this has been shown to further increase the spread of bacteria, as the “footbath” is rarely exchanged between infected and healthy animals, and can therefore become a pool of bacteria. In addition, treatments often have some kind of side effects, which healthy animals should not be exposed to.

We would never do that with humans; risk treating even healthy people and causing possible sequelae, says PhD-student Lex Roelofs and continues: But if we can lower the threshold and make it easier to detect and treat only the affected animals, hopefully the method can be replaced by something better.

So, how can the research team at SLU offer a solution to the situation?

Color test illuminated by the bacteria

The short-term goal is to create a test that, through a blood or milk sample, can indicate which individuals in a group of cows carry the infection, whether or not it is visible in the hooves.

The research team is using the previously developed ELISA tool, which in very simple terms can be described as a “color test”. When a sample is dropped into the container and found to be infected, the color of that sample changes. This is possible because the researchers track the levels of antibodies in each sample/individual. The technique is already used for diagnostics in many different diseases, and now seems to be proving useful in this area too.

Halfway through the project: “Letting joy lead the future”

Lex Roelofs is now halfway through the project, and the future looks bright.

In addition to successfully developing individual tests, the research team also hopes that the method can be used to map and monitor the spread of infection across the country, an important aspect of the overall effort to reduce infectious diseases.

I think it is possible to go all the way, we are getting good results and have several ideas on how to refine the tools we are working with, he says.

A fantastic improvement for both the welfare and production of the farm animals involved. With results and tools that could eventually be used to create a vaccine as well.

I have no long-term plan for my career. As long as I feel passion and joy in what I do, I want to continue doing it, concludes Lex Roelofs.
Portrait of a man (phd-student Lex Roelofs) in the laboratory dressed in lab gown holding a petri dish.
Photo: Lisa Chröisty, SLU

Facts:

  • The project is funded by the Seydlitz MP Foundation and the Petra Lundberg Foundation and is expected to run from 2022-2026/2027.
  • The PhD student in the project is Lex Roelofs, together with a research group consisting of:
    • Sara Frosth, main supervisor, researcher and  lecturer in veterinary bacteriology at the Swedish University of Agricultural Sciences, SLU. 
    • Anna Rosander, researcher and associate professor in veterinary bacteriology at SLU.
    • Joakim Bjerketorp, researcher in Microbiology at SLU.
    • Ingrid Hansson, veterinarian and professor in veterinary bacteriology.

The project can be easily broken down into the following intermediate and final objectives:

Sub-goal: To develop an improved and objective diagnostic tool for digital dermatitis in both cows and sheep

Final goal: To also be able to use the diagnostic method to similarly sample the contents of large milk tanks, detect whether any infection is present in any of the farm's dairy animals, and thus enable mapping and monitoring of the spread of infection throughout the country's farms.

In the very long run, it is also possible that a vaccine against the disease could be developed, based on the experience and knowledge gained from this project.

NOTE: The project studies both cows and sheep, although this article focuses mostly on cows, which is the animal species with the largest test data and thus the focus is placed.

Contact

  • Lex Roelofs, PhD-student
    HBIO, Bacteriology, Virology, Food Safety and Veterinary Public Health