A number of beef farmers held a protest outside the EU Commission offices in Dublin in relation to negotiations on a trade deal with the South American trading bloc, Mercosur.
The IFA, which organised the protest, accused the commission of double standards.
"We will be there to oppose EU Commission plans to sell out Irish farming in a deal with the devil that is Brazil and its new President Bolsonaro," IFA President Joe Healy said.
"It is totally unacceptable that the commission is prepared to sacrifice Irish and European farmers, but they are also giving the green light to the further destruction of rainforests.
"Farmers are sick of the double speak from the EU Commission which lectures us on climate change, but is prepared do a deal with a country with a climate destruction agenda."
Edmund Graham, beef chairman of the Irish Cattle and Sheep Farmers' Association, said EU leaders are pushing for "very challenging climate change restrictions on EU farmers while at the same time ignoring the massive climate change and environmental downsides of importing increased quantities of Brazilian beef under a Mercosur deal".
He said that ICSA members had met EU negotiators over the Mercosur deal and highlighted their concerns for the Irish beef sector.
"ICSA has met the EU negotiators on Mercosur on several occasions in 2019 and we have left them in no doubt that a Mercosur deal would be an unmitigated disaster for the Irish beef sector," he said.
"The risk is all the more pronounced because of Brexit uncertainty."