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Potty-training calves could lower climate cost of cows

Seth Borenstein, September 14, 2021 7:00PM AP

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Scientists say they have successfully toilet-trained cows to urinate in a designated area as part of a study aimed at reducing livestock greenhouse gas emissions. Picture: Research Institute for Farm Animal Biology/AFP media_cameraScientists say they have successfully toilet-trained cows to urinate in a designated area as part of a study aimed at reducing livestock greenhouse gas emissions. Picture: Research Institute for Farm Animal Biology/AFP


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Who knew cows could be toilet-trained as easily as toddlers? Well, scientists put the task to the test and 11 out of 16 cows learned to use the “MooLoo” when they had to go.

Just like parents, researchers used sweet treats to coax* the cows to push through a gate and wee in a special pen. It took only 15 days to train the young calves – not bad when you consider that many kids take quite a bit longer to master the art.

“The cows are at least as good as children aged 2-4 years, at least as quick,” said study senior author Dr Lindsay Matthews, an animal behavioural* scientist at New Zealand’s University of Auckland, who worked with colleagues at an indoor animal research lab in Germany.

The study results were published this week in the journal Current Biology – and while Dr Matthews admitted the idea began as a joke, he said the massive amount of urine waste is a serious environmental issue.

A cow learns to urinate in the MooLoo - Research Institute of Farm Animal Biology. For Kids News 2 media_cameraA calf learning to urinate in the MooLoo can expect a sweet treat as its reward. Picture: Research Institute of Farm Animal Biology

Urine contains nitrogen*, and when mixed with faeces becomes ammonia*, which is an environmental issue with acid rain and other problems – including tainting* the water with nitrates* and creating the airborne pollutant nitrous oxide*, Dr Matthews said.

And cows do wee a lot. A single cow can produce about 30 litres of urine a day, Dr Matthews said. Indeed, the World Resources Institute says agriculture accounted for 11.9 per cent of global greenhouse gas* emissions* in 2018. Of this, 5.9 per cent came from livestock and manure.

“I am not surprised they can train calves to urinate in set locations, but I am surprised no one has demonstrated this before,” said Duke University animal cognition scientist Professor Brian Hare, who wasn’t part of the research. “The critical question is, can it and will it scale?”

If it can be done, toilet training animals would make it easier to manage waste products and reduce greenhouse gas emissions, said Professor Donald Broom, an animal welfare expert at the University of Cambridge in England.

At the lab is Dummerstorf, Germany, researchers mimicked a toddler’s training, putting Holstein cows in the special pen, waiting until they urinated, then giving them a reward: a sweet liquid of mostly molasses. And cows do have a sweet tooth, Dr Matthews said. If the cows urinated outside the MooLoo after the initial training, they got a squirt of cold water instead.

A cow learns to urinate in the MooLoo - Research Institute of Farm Animal Biology. For Kids News 1 media_cameraThe success of the MooLoo could be the gateway to training other animals to go in the same place, offering the possibility of new solutions to reducing greenhouse gas emissions. Picture: Research Institute of Farm Animal Biology

There are two important considerations coming out of the study, including that researchers gave diuretics* to the cattle to get them to urinate more, because they had limited time to run the experiments under ethics* guidelines.

The more pressing issue – in more ways than one – is that they only trained cows to use the MooLoo to urinate, not defecate*.

Urine is the bigger problem, at least in Europe, according to Dr Matthews, but he predicted cows could be trained to poo in a certain place too.

While dogs, cats and horses can all be toilet-trained, they already show a desire to go in a special place, but cows don’t display such a preference, Dr Matthews said.

But the biggest environmental problem for livestock remains the heat-trapping gas methane* they emit in belches and flatulence, a significant source of global warming. Unfortunately the cows can’t be trained not to belch or fart.

“They would blow up,” Dr Matthews said.


  • coax: persuade, convince, influence
  • behavioural: relating to behaviour
  • nitrogen: colourless, odourless gas
  • ammonia: colourless gas with a strong, distinctive smell
  • tainting: polluting, contaminating, spoiling
  • nitrous oxide: a colourless gas, also called laughing gas, used for sedation and pain relief
  • greenhouse gas: gases in Earth’s atmosphere that trap heat
  • emissions: the production and release of something
  • diuretics: substances that increase urine production
  • ethics: branch of philosophy dealing with moral principles
  • defecate: release or discharge faeces from the body
  • methane: colourless, odourless flammable gas, the main constituent of natural gas


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  1. How many days did it take to train the young calves?
  2. A single cow can produce approximately how much urine per day?
  3. What did the calves get as a reward for using the pen?
  4. Which animals already show a preference for going in the same spot?
  5. What would happen if cows were trained not to burp or fart?


1. Cow flatulence device!
A huge environmental problem that contributes to global warming is methane gas, produced by a cow’s burps and flatulence! As you’ve read in the Kids News article, scientists have so far managed to toilet-train cows to do wee in a certain spot, but no one has managed to come up with a possible solution to reduce or catch the gas when they burp or fart.

Work with a partner to invent a device or machine that may be able to help with this problem. You can be as creative and as out there as you like. Draw and label your design, give it a name and present to your class.

Time: allow 40 minutes to complete this activity
Curriculum Links: Design and Technologies; Personal and Social; Critical and Creative Thinking

2. Extension
Which other animals do you think could be toilet-trained similar to the cow experiment?

What could we do with this waste product to reduce its effect on the environment?

Which animals do you have that are toilet-trained and how did you train them?

Time: allow 10 minutes to complete this activity
Curriculum Links: Science; Critical and Creative Thinking

For real life?
The last quote in this article from Dr Matthews says, “They would blow up.”

He was referring to cows. What was the context of this statement? And was he serious?

Create a cartoon depicting the last part of the article, including Dr Matthews’ statement.

Add more dialogue or narration to your comic to put it into context. Decide if it will be a humorous cartoon, or an experiment gone horribly wrong.

Extra Reading in animals