Researchers are working with farmers across England and Wales in a bid to make a "huge difference" by reducing methane production and feed costs for dairy cattle.

To summarize: people have known that cows’ methane production can be reduced with an appropriate diet for quite some years. There has been a fair bit of searching for what that diet could be - tropical algae from high seas may produce the right outcome but aren’t readily available where the cows graze.

It is nice to learn that daffodils also do the trick, and reduce methane production by “at least 30%” (a cautious estimate, some results using artificial cow stomachs have given a reduction of 96%).