Carter, who stepped down in 2018, was board chairman and one of the industry representatives during the NAWAC farrowing crate review. There was a complete and thorough investigation into farrowing systems completed by NAWAC in 2016, he said.
"There has been no new science since to suggest any need for significant change. For the benefit of an animal's welfare these decisions must only be made on science not emotion or perceptions which can have unintended consequences that cause more harm than good. Emotive and perceptive decisions should be left solely for the individual consumer to make at their point of purchase," he said.
A farrowing system was used for about four weeks; from just prior to birth through to weaning at up to four weeks of age. During that time, the sow did not need to concern herself with safety, predator threat, shelter, warmth or seeking food or water, and could focus on nurturing her piglets.
The piglets had areas that were warmed at a higher temperature than the sow, which helped provide them freedom from the sow accidentally laying on them and killing them with her weight, Carter said.
Sows were large (250kg plus) animals which gave birth to large numbers of piglets, each roughly weighing 1.5kg. Accidental lay-ons were the biggest driver of mortality in pig production.
"Those who understand our animals see the farrowing system for what it is, a maternity unit of care," he said.
In a statement, SAFE and NZALA welcomed the High Court's judgement, with SAFE chief executive Debra Ashton describing it as a historic day for animals.
"After exhausting all other avenues to free mother pigs from cages, we had no other option but to take this landmark case to court," she said. It was the first time a Code of Welfare had been challenged in court.
New Zealand Pork animal welfare scientist and adviser Kirsty Chidgey told RNZ that more than half of pig farmers used farrowing crates and it was important to consider piglets.
About 60 per cent of pork consumed in New Zealand came from countries overseas with worse animal welfare practices than New Zealand.
One consequence could be fewer farms existed in New Zealand and more pork would be imported from those countries, Chidgey said.
