US cattle farmers have urged the country's government to once again thwart attempts by Brazilian meat giant JBS to expand in the US.

R-CALF USA has written to the US Department of Justice asking for JBS's plans to take majority control of Pilgrim's Pride, the country's largest poultry processor, to be blocked.

It is not the first time that JBS has seen opposition to its ambitions to grow in the US. In February, the company dropped plans to buy US firm National Beef Packing Co. after the regulators filed a lawsuit to block the deal.

Bill Bullard, CEO of R-CALF USA, said US cattle farmers were against JBS's planned acquisition of Pilgrim's Pride over fears the Brazilian group could "manipulate" the market for proteins Stateside.

"The demand and price for cattle is influenced by the supply and price of competing proteins such as pork and poultry, and prices received by R-CALF USA members for their cattle are particularly susceptible to increased poultry supplies," Bullard said.

"We estimate that JBS's share of fed cattle packing capacity in the US is now over 25%, and with the acquisition of the vertically integrated Pilgrim's Pride - which controls over 20% of US poultry production - JBS could further manipulate the competing protein market in the United States."

JBS's increased scale in the US could lead to lower poultry prices for consumers and lead to lower beef consumption, the pressure group said.

"JBS and Pilgrim's Pride are currently fierce competitors in the meat protein market, and a merger between the two would most definitely reduce competition and result in the exploitation of both producers and consumers," Bullard added.

Officials at JBS did not respond to a request for immediate comment.