China pledged to increase purchases of US agricultural products as part of the agreement, which is meant to reduce tensions after nearly two years of a tit-for-tat tariff war. It included a promise by China to purchase at least an additional $12.5 billion worth of US agricultural goods in 2020 and at least $19.5 billion over the 2017 level of $24 billion in 2021.

However, traders remain uncertain about the size and timing of future purchases because China said firms will buy US products based on "market conditions."

"There's a little bit of uncertainty - scepticism, maybe - as to how much beef may be ultimately in the Phase 1 China trade deal," said Mike Sands, an independent US livestock market analyst.

April live cattle futures ended down 0.025 cent at 127.225 cents at the Chicago Mercantile Exchange. March feeder cattle futures slipped 0.325 cent to 144.675 cents per pound.

February lean hog futures dipped 0.325 cent to 67.350 cents per pound at the CME. The April contract ended 0.275 cent weaker at 73.825 cents a pound.

US farmers are hoping China will increase imports of American meat, particularly pork, because its hog herd has been decimated by ASF. China increased its purchases of several types of meat last year as the disease outbreak sharply reduced pork production.

The hog futures market has already priced in expectations for bigger US pork sales to China, Sands said.

"Now the question is, can we get some verification that that's actually true?" he said.

Chinese beef importers are seeking to renegotiate prices previously agreed when they closed deals to buy dozens of shipments from Brazil because values are too high, according to a report in the online edition of a local newspaper.

Separately, Germany and Poland are discussing new action to prevent the spread of African swine fever in wild boars in Poland close to the German border, Germany’s agriculture ministry said.