CHICAGO, Aug 28 (Reuters) - Chicago Mercantile Exchange feeder cattle futures gained on Monday, supported by consumer demand and continued tightening of available cattle, analysts said.

"I think we probably did get a little help here from retail movement over the last week," said Alan Brugler, president of Brugler Marketing, noting the U.S. Labor Day holiday is traditionally the last big barbecue weekend of the summer.

Most-active October feeder cattle jumped 3.050 cents to 257.025 cents per pound, while October live cattle inched up 0.375 cents to 181.550 cents per pound.

Boxed beef prices eased after strong gains last week, with choice cuts drifting 86 cents lower to $317.04 per cwt., while select cuts slipped 58 cents to $292.09 per cwt.

Cash cattle trade was steady in the northern plains at $185.00 per hundredweight (cwt), while the southern plains were steady at $179.00 per cwt, according to the U.S. Department of Agriculture.

Cattle processors slaughtered 125,000 head, up 8.70% from the same period a year ago, the USDA said.

Meanwhile, CME lean hog futures gained for a fourth consecutive session, supported by consumer demand ahead of the U.S. Labor Day holiday, Brugler said.

"(Pork) bellies were back up today," he said. "They got hammered on Friday."

The most-active October futures firmed 2.025 cents to 81.850 cents per pound.

Wholesale pork carcass cutout added $2.63 to $96.05 per cwt.

Pork processors slaughtered 476,000 head, up 5,000 from the same day last week but down 1.24% versus the same period last year, the USDA said.

The CME's Lean Hog Index, a two-day weighted average of cash prices, last fell to 95.00 cents per pound. (Reporting by Christopher Walljasper in Chicago; Editing by Krishna Chandra Eluri and Maju Samuel)