How to toilet train your cow

PUPPIES CAN be taught. So can human children, though not for the first couple of years. Now, in the hope of fighting climate change, Dr Jan Langbein, of the Fredrich-Loweffler-Institut in Germany, and his colleagues hope they can train cows to use the toilet, too.

Cow urine contains urea, a nitrogen-rich compound that, when broken down by enzymes in cow faeces, is converted into ammonia. Bacteria in the soil, in turn, convert that ammonia into nitrous oxide. Best known as a dental anaesthetic, the stuff is also a potent greenhouse gas. And agriculture is a big source of it. In the European Union, livestock farming accounts for around 70% of ammonia emissions.