In a bid to stop stock effluent spilling on to roads, Environment Southland and the Road Transport Association have initiated the forms as evidence that cattle have been off green feed for at least 12 hours before being transported.
"The forms require farmers to certify that they have stood stock off green feed for at least 12 hours before loading and that they understand if this is not the case, that they could be liable for any discharge of effluent on to public roads while the animals are being transported," council chairman Stuart Collie said in a statement.
He suggested stock were given dry feed and water before being transported.
But Federated Farmers say that signing the declaration would make farmers liable for any effluent spillage on roads, although they had no control over the load.
Dairy Farmers of New Zealand Southland chairman Rod Pemberton said farmers did not know whether the effluent tanks on trucks were full or empty, or whether other farmers' stock in the load met the criteria.
Environment Southland had not built any permanent effluent disposal sites for trucks, unlike the Otago Regional Council, which had seven.
Environment Southland has an agreement with two trucking companies to use their private disposal systems, but both are in the Lumsden area.
"Environment Southland are sitting on their hands by not building effluent stations," Mr Pemberton said.
There were also animal welfare issues in keeping pregnant cows off feed for 12 hours at a time of year when cows were losing condition after being dried off.
Mr Pemberton said some cows were sent to Central Otago for winter grazing, which could mean six hours in a truck, in addition to the 12 hours they had to be stood off green feed.
The 12 hour stand-down went against advice from veterinarians and Fonterra, who suggested four to six hours, Mr Pemberton said.
He suggested farmers liaise with their vets to decide the best pre-transport action rather than co-operate with a directive which he described as "a knee-jerk reaction".
Mr Collie said the declarations were agreed to following a meeting between the council and transport operators last week and were the result of public complaints about effluent on roads.
He agreed the temporary dumping sites were not sufficient, or on routes that could be easily used, but said that meant farmers and trucking companies had to work harder to keep spillages off roads.