A US meat industry lobby group has called on state authorities to step in and block JBS's proposed acquisition of Pilgrim's Pride.

Last month, JBS and Pilgrim's Pride struck a deal that would see the Brazilian meat giant take a majority stake in the struggling US poultry producer. Through the merger, JBS would become the world's largest protein company.

In a bid to prevent the completion of the deal, R-Calf USA has contacted the 17 state attorneys general who helped block JBS's proposed acquisition of National Beef Packing Co. last year.

R-Calf president Max Thornsberry described the deal as "anti-competitive" and warned that it could have a negative impact on consumers as well as the meat industry's "economic viability". 

"Today, we are faced with a new merger proposal by JBS that, like its proposal in 2008, would further reduce competition in US meat and cattle markets and harm US consumers and US producers," he said.

"JBS now proposes to acquire Pilgrim's Pride, the largest poultry broiler company in the United States, and we are once again seeking your assistance to prevent the further loss of competition, as well as to protect both consumers and producers against anticompetitive trade practices."

The industry body had previously contacted the US Department of Justice and added that it will contact the remaining 33 state attorneys general later this week.

Officials at JBS were not immediately available for comment.