The toilet training of cows could have great environmental benefits.
Auckland University researchers, along with German colleagues, have shown bovines can be trained to use a latrine, using food as a reward.
Study author, Lindsay Matthews, told Mike Hosking Dutch modelling shows if you could capture 80 percent of the urine, you'd reduce ammonia by 50 percent.
"We haven't done similar modelling here, but it would be substantial for the nitrates going into the water and the nitrous oxide going into the air."
Lindsay Matthews says it took up to 15 days to train each cow but the process could be automated.