Chicago Mercantile Exchange (CME) lean hog futures closed mostly lower on Friday, pressured by government data showing the US hog herd expended 2% during the last quarter as well as worries about a potential strike at US ports next week, Reuters reported, citing analysts.

Some 45,000 union workers could walk off the job at seaports on the East and Gulf Coasts starting Monday, cutting off vital trade arteries. The dispute could affect availability of a range of goods from bananas to cars shipped via container, while creating weeks-long backlogs at ports.

"A strike could bring pressure on the hogs as it would hit exports of pork coming out of the East Coast," said Dan Norcini, an independent trader.

CME December lean hog futures settled down 0.550 cent at 73.375 cents per pound and February hogs ended down 0.325 cent at 77.500 cents.

Traders were digesting data from a pair of US Department of Agriculture (USDA) reports released after Thursday's market close. The USDA said in its quarterly hogs and pigs report that the US hog herd as of September 1 was 76.5 million head, up slightly from a year earlier and in line with trade expectations. The herd was up almost 2% from June 1.

However, Thursday's monthly USDA Cold Storage report was supportive, Norcini said, in showing a 30% year-on-year drop in stocks of frozen pork bellies as of Aug. 31.

CME live cattle futures closed mostly lower on Friday. Benchmark December live cattle settled down 0.350 cent at 184.475 cents per pound, retreating after climbing to 185.600 cents, the contract's highest since Aug. 1.

CME November feeder cattle futures rose, settling up 0.725 cent at 245.700 cents per pound.

The USDA priced choice cuts of boxed beef on Friday afternoon at $296.69 per hundredweight (cwt), up 32 cents from Thursday's four-month low. But select cuts fell by 29 cents, at $282.08 per cwt.

The USDA reported Friday's cattle slaughter at 116,000 head, up from 108,000 head a week earlier.