Numerous beef producers have reacted angrily to proposals to re-define the age of prime cattle as a measure to reduce the sector's carbon footprint.
The National Beef Association (NBA) has proposed that the definition of prime cattle should be restricted to those slaughtered below 28 months old.
Currently, the majority of UK cattle slaughtered between the ages of 12-30 months are classified as prime cattle.
The industry body added that a 'carbon tax' should be introduced for animals slaughtered above that age.
Responding to the proposals, the Farmers' Union of Wales (FUW) said it had received 'many calls from angry members'.
FUW president Glyn Roberts said: "Many highlighted the particular impact the proposal would have for traditional breeds and certain farming systems which are of particular importance to the environment.”
Mr Roberts, who runs a beef and sheep farm in North Wales, agreed that the carbon benefits of finishing animals more quickly were well known for certain farming systems.
However, for more traditional systems where animals are finished over a longer period, such a 'black and white proposal' did not make sense from an environmental perspective, including in relation to carbon.
He added: “These concerns will no doubt be raised at a joint meeting of our Livestock, Wool and Marts and Hill Farming and Marginal Land Committees later this month.
"While I do not want to pre-empt the outcome of that meeting, I can guarantee that there will be some very angry reactions to the NBA’s proposals in line with those already expressed by the Scottish Beef Association."