The Prince of Wales says he has faced a "chorus of ridicule" over his campaign to protect rare native breeds of cattle, sheep, pigs and chickens.
But he said his efforts had been worth it because "surprise, surprise" such livestock was making a comeback.
He went on to criticise "crazy" European Union laws banning the sale of seed from historic varieties of plant.
Prince Charles was speaking to BBC Radio 4's Gardeners' Question Time to mark its 60th anniversary.
He bemoaned what he said was "the craziness of what we've done to this world", calling it "lunacy".
The prince champions many environmental causes and has won awards for his green work.
Among his passions are organic farming and conserving Britain's traditional farming methods.
"Which is why I have been going on for all these years to a chorus of ridicule about the importance of protecting and preserving rare native breeds of cattle, sheep, pig and chicken," he said.
"And sure enough now, surprise, surprise, they're beginning to come back."
Prince Charles' latest target is EU seed directives which he says have led to the loss of ancient varieties of plants developed over thousands of years.
"What could be crazier than reducing ourselves to far too few varieties and finding, at the end of the day, that maybe they are then more and more subject to disease and complications?" he said.
The prince also told the programme he enjoyed working in his organic garden at Highgrove House, in Gloucestershire, but because of a bad back, he had to kneel down to plant or dig.
Hear the interview in full on Gardeners' Question Time on BBC Radio 4 at 1400 GMT on Sunday 8 April.