Some very special cows are walking around the stables in Foulum, a little city outside Viborg in Denmark. The cows have been implanted with a so-called fistula. This is a kind of window leading directly into the stomach of the cow.
Through a tube, researchers can take samples and observe what is happening in the cows' stomachs when the cows eat different types of feed. The feed can have a huge impact on how much cows belch, and thus on how climate-friendly they are.
Experiments in the US and Australia have shown that adding the tropical algae Asparagopsis to feed means cows emit 80 percent less methane. The problem is that Asparagopsis contains the substance bromoform, which can potentially cause cancer in humans and also harm the ozone layer.
Therefore, the hunt is on for other species of algae with the same effect, but without bromoform. This is what Mirka Mølgaard Thorsteinsson studied in her Ph.D., which she has just submitted at the Department of Animal and Veterinary Sciences at Aarhus University.
"I've researched into the effect of a large number of algae that grow here in the Nordic region. I hope that they can help reduce the methane emitted by the cows and, at the same time, perhaps replace the soy we import from South America," she says.
In September, Mirka will defend her Ph.D. dissertation at the Department of Animal and Veterinary Sciences.
She has submitted the dissertation—and she has already started new experiments in her new role as a postdoc.
She loves working with the cows. The cows usually only have numbers, but she has given them all names. Every day she checks the cows, pets them, and makes sure that they are having a good day.
Happy cows give better results. She also thinks that the cows should be happy. And according to Mirka, no cows in Denmark are cared for better than those at AU Viborg.
The artificial cow stomach
Before Mirka went to the university cowsheds to feed the special cows with algae, she tested the various algae species in an artificial cow stomach. This is a small apparatus for investigating whether the algae have reduced methane emissions, she explains.
"An artificial cow stomach is actually just a small bottle that I've filled with stomach fluid from a cow. Then I added the type of algae I want to examine and a little buffer to act as the cow's saliva," she says.