Researchers have potty-trained cows in a bid to reduce ammonia emissions caused by their waste.
On a farm where cows freely relieve themselves as they graze, the accumulation and spread of waste can contaminate soil and waterways.
While this can be controlled by confining the cows in barns, in these conditions their urine and faeces combine to create ammonia – an indirect greenhouse gas.
In a new study, researchers found that the animals can be potty-trained, allowing waste to be collected and treated, thereby cleaning up the barn, reducing air pollution, and creating more open, animal-friendly farms.
Co-author Jan Langbein, an animal psychologist at the Research Institute for Farm Animal Biology (FBN) in Germany, said: “It’s usually assumed that cattle are not capable of controlling defecation or urination.”
He added: “Cattle, like many other animals or farm animals, are quite clever and they can learn a lot.
“Why shouldn’t they be able to learn how to use a toilet?”
To potty-train the calves, a process they dubbed MooLoo training, the research team with scientists from FBN, FLI (Germany) and the University of Auckland (New Zealand) worked backwards.
They started off by rewarding the calves when they urinated in the latrine, and then they allowed the calves to approach the latrines from outside when they needed to urinate.
The ammonia produced in cow waste does not directly contribute to climate change, but when it leaches into the soil, microbes convert it into nitrous oxide, the third-most important greenhouse gas after methane and carbon dioxide.
Researchers say agriculture is the largest source of ammonia emissions, with livestock farming making up over half of that contribution.
Dr Langbein, said: “You have to try to include the animals in the process and train the animals to follow what they should learn.
“We guessed it should be possible to train the animals, but to what extent we didn’t know.”
To encourage latrine use, researchers wanted the animals to associate urination outside the latrine with an unpleasant experience.
Dr Langbein explained: “As a punishment we first used in-ear headphones and we played a very nasty sound whenever they urinated outside.
“We thought this would punish the animals – not too aversively – but they didn’t care. Ultimately, a splash of water worked well as a gentle deterrent.”
Over the course of a few weeks, 11 out of the 16 calves in the experiment were successfully trained.
Researchers said the calves showed a level of performance comparable to that of children and superior to that of very young children.
They hope that with more training the success rate can be improved, and they want to transfer their results into real cattle housing and to outdoor systems.
Dr Langbein hopes that “in a few years all cows will go to a toilet”.
The research is published in the journal Current Biology.