CHICAGO, March 14 (Reuters) - Chicago Mercantile Exchange cattle futures climbed on Monday as traders attempted to make sense of changing trade restrictions and allowances.

"The market's trying to sort out all these trade protection measures," said Alan Brugler, president of Brugler Marketing. "Everybody seems to want imports, and nobody wants to export anything."

CME April live cattle rose 3.025 cents to 140.325 cents per lb, while May feeder cattle added 3.725 cents to 167.450 cents.

Brazil is expanding its meat exports, with Canada now allowing imports of Brazilian beef and pork, the South American country's Agriculture Minister Tereza Cristina Dias said.

Meanwhile, U.S. boxed beef prices firmed, with choice cuts gaining 80 cents to $255.51 per cwt, the USDA said, while select cuts added 83 cents to $249.94 per cwt.

Cattle slaughter is maintaining its pace, with 125,000 head processed on Monday, in line with last week's pace.

Hog futures also firmed, supported by seasonal demand, while high feed costs continue to cap herd expansion.

CME April lean hog futures lost 0.525 cents to end at 102.200 cents per pound. June hogs added 1.175 cents to finish at 119.350 cents per pound.

Hog producers are still hesitant to expand production, Brugler said, pointing to higher feed prices as a deterrent.

"It makes it hard to justify expanding your sow herd," he said.

The CME's lean hog index, a two-day weighted average of cash hog prices, climbed 1.125 cents to 119.300 cents per pound. (Reporting by Christopher Walljasper; Editing by Devika Syamnath)