As part of a research program to reduce greenhouse gas emissions, scientists taught cows to urinate in a designated area.
The ability to collect urine could significantly reduce the environmental impact of cattle farming, explained a team of New Zealand and German scientists in an article in the current issue of Current Biology.
The scientists trained 16 calves to urinate in a latrine pen with the help of feed rewards.
The results are comparable to what can be expected from a three-year-old child, the researchers said.
The idea of training cows to collect their urine originally came about as a joke, says animal behavior researcher Lindsay Matthews.
"People's reaction is, of course, 'mad scientists'," but that makes perfect sense.
Because the urine excretion of cows is problematic in two ways: They release the greenhouse gas nitrous oxide, commonly known as laughing gas, and they contain large amounts of nitrate, which is deposited in the soil and in water.
"If we could collect 10 or 20 percent of the urine output, we could significantly reduce greenhouse gas emissions and nitrate leaching," says Douglas Elliffe of the University of Auckland.
The collected urine should then be treated.
The big herds are the challenge
According to Elliffe, the research shows that toilet training for cows is fundamentally possible.
The challenge now is to expand the concept to train large herds and adapt it to environments like New Zealand, where the animals spend most of their time outdoors rather than in the barn.
In New Zealand, agriculture causes around half of greenhouse gas emissions, mainly in the form of methane and nitrous oxide.
That is why intensive research into possible solutions has been carried out for years.
Other projects are the breeding of farm animals with low methane emissions, the use of alternative feed or even vaccinations of animals so that they produce less harmful gases.