Concerns have been raised over a practice known as intensive winter feeding, with some South Island farmers being accused of overcrowding their paddocks and turning them into mud baths.
It comes after distressing images were released of cattle being unable to move after their paddocks were left knee-deep in mud.
Federated Farmers Otago president Simon Davies said the images are "a poor example of winter feeding of stock".
"Yeah, I would be embarrassed if that was on my farm," Mr Davies said.
The images have angered Federated Farmers and the New Zealand Veterinary Association, which says cattle in this situation can't exhibit natural behaviour.
New Zealand Veterinary Association Chief Veterinary Officer Helen Beattie said, "One of those things for cows is they like to lay down and chew their cud and have a bit of a rest, and we know on muddy subtracts that they reduce their lying time significantly".
"If the animals aren't healthy and aren't happy, they won't perform and they won't grow," Mr Davies added.
The feeding practice some farmers use for efficiency is mostly seen in the South Island, but some are crowding too many cattle on a single piece of land.
"To be honest, a lot of it, I believe, is it's an education thing - farmers have traditionally done things a certain way," Mr Davies says.
Ms Beattie said health issues like "mastitis and hoof health are important to consider".
"We know there's an increase in incidence of mastitis and lameness after wintering for long periods of time on mud," Ms Beattie said.
However, it's not just the welfare of the animals that are causing concern, but also the run-off from the farms into nearby waterways.
Now, Fish and Game New Zealand are calling for a change.
Fish and Game CEO Martin Taylor said, "The reason why Federated Farmers, Fonterra and other dairy leaders are not saying it needs to stop, is cause they don't want their farmers to have their costs go up".
Ms Beattie says that animals encountering mud in the winter in New Zealand is "a given" but "there's a different conversation around expecting animals to live up to their bellies in mud for weeks on end in winter".
"I think that's where conversation needs to start," she said.
The Government currently has no rules or regulations in place around the practice, but "if you think it looks wrong, it's probably wrong," Mr Davies said.