He says Da Costa admitted removing the teats by placing a rubber ring on them and cutting them off two days later with a pair of scissors.
He failed to use any form of pain relief.
"In explanation for his actions, Da Costa said the cows had bad lacerations to their teats and he considered it the quickest and cheapest way to fix the problem," says Mr Green.
"He said the lacerations were already causing the cows pain and he didn't believe his actions caused them any more pain."
Mr Green says expert veterinary opinion stated that sensory innervation of the teat is dense and therefore very sensitive to trauma and other painful stimuli.
Any teat surgery there requires analgesia and should only be undertaken by a veterinarian.
It was highly unlikely that all 12 cows would have required treatment by teat amputation.
"Teat occlusion using the method employed by Da Costa is a draconian practice with no place in modern dairy farming."
Da Costa was convicted and fined $3,750 when he appeared in the New Plymouth District Court today.