Thousands of people attended a protest in Athlone, Co Westmeath, on Saturday against the EU-Mercosur trade deal.
On Friday, European Union states approved the agreement with Brazil, Argentina, Paraguay and Uruguay, although it still needs to be backed by MEPs.
The Irish Government voted against the deal in its current form, with senior Cabinet figures insisting that negotiations were not finalised.
Many at the protest said they were concerned the deal would result in lower-quality beef being imported into Ireland from South America, affecting Irish farmers’ livelihoods and the quality of meat consumed here.
Paddy Buggy, a beef farmer and Fine Gael councillor in Portlaoise, Co Laois, said the agreement would allow “poor quality beef into the EU”.
Mr Buggy said he was concerned beef from South America would contain substances that were banned in the EU such as hormones and growth promoters.
“All those are banned here – banned for specific reasons, they are damaging to people’s health,” he said.
Mr Buggy accused the European Union of “hypocrisy”, saying Irish farmers had followed all the rules, but were now being “penalised”.
Farmers from across the country drive through Athlone to protest against the Mercosur deal. Photograph: Enda O’Dowd
The protest, organised by Independent Ireland, was attended by politicians and farming organisations.
Independent Ireland MEP Ciaran Mullooly told the rally that Irish consumers did not want to eat “contaminated” beef. He urged his fellow Irish MEPs to vote against the deal.
Seán Sherman, a farmer based in Rathdowney, Co Laois, said “beef and sheep is my life”.
“We have three kids in education, and they’re encouraged to do everything that they want to do,” he said.
“Farming isn’t where they’re pitching their sites because for the last 15 years it hasn’t been profitable and now we’re seeing a further step here to erode it completely.
“This is a rural country, and farming is the backbone of it for lots of reasons. We’re regulated almost out of existence, in terms of standards. We’ve raised the bar very high and yet we’re being sold out, so it’s a difficult pill to swallow.”
Farmers Paddy Buggy and Seán Sherman at the protest. Photograph: Órla Ryan 
Protesters vented their anger at Brussels. Photograph: Enda O’Dowd 
Farmers in convoy at the demonstration. Photograph: Enda O’Dowd
Rosemary Moran, a dairy farmer from Glasson, Co Westmeath, said the Mercosur deal proved many politicians “don’t care” about farmers.
“I worked so, so hard on farming. I followed the rules and I followed the regulations, and now it’s okay for that woman in Brussels, Ursula [von der Leyen] to bring this in,” Ms Moran said. “Why undo the good things now?”
Leslie Northridge fears the deal will result in ‘a lot of youngsters’ leaving agriculture sector. Photograph: Enda O’Dowd
Leslie Northridge, a farmer based Midleton, Co Cork, said he travelled to the protest because he wanted to “keep our industry alive, to make sure children, going forward, have a have a future in farming”.
Mr Northridge said the deal would result in “a lot of youngsters” leaving agriculture and getting jobs in other industries.
“Farmers will be decimated, there will be farms left idle.”
Kerry Independent TD Danny Healy-Rae said the deal represented “the death knell for Irish farming”.
“We at least deserve fair play, and we’re not getting it now. The regime that’s in place in the EU seems to be opening this thing up to the rest of the world.
“And we’re only a small, little country. We can’t compete in that market. I don’t think that is fair, or we’re going to survive in it.”
Supporters of the trade deal, however, say it offers access to new markets for EU businesses, including those in pharmaceuticals, tech and chemicals, and helps to combat US tariffs.