CHICAGO, March 25 (Reuters) - Chicago Mercantile Exchange live cattle futures weakened for the fifth consecutive session on Monday after the U.S. government reported bigger-than-expected placements into feedlots last month.

The U.S. Department of Agriculture, in a report issued after trading ended on Friday, said 1.89 million cattle were placed into feedlots in February, up 9.7% from a year ago and above a range of pre-report estimates.

The large increase surprised some analysts, as ranchers slashed the size of the U.S. cattle herd due to a drought that reduced pasture lands available for grazing. However, placements rose because February had an extra "leap year" day compared to last year, and winter weather in January delayed some placements until February, analysts said.

The USDA also reported there were 11.8 million cattle in feedlots as of March 1, up 1.3% from a year earlier. That was at the top end of analysts' expectations and above the average estimate for a 0.9% increase.

CME April live cattle futures on Monday settled down 1.3 cents at 186.200 cents per pound. Benchmark June cattle fell 1.300 cents to 181.600 cents and touched the lowest price since Feb. 29.

May feeder cattle slid 1.15 cents to finish at 252.625 cents per pound.

After trading ended on Monday, the USDA reported there were 442.8 million pounds of beef in U.S. cold-storage facilities at the end of February, down 6% from the previous month and down 12% from last year. That was the lowest for that date since 2014.

Frozen U.S. pork supplies were down 1% from the previous month and down 12% from last year at 456.5 million pounds. That was the lowest for the end of February since 1997.

Benchmark CME June hogs settled up 1.975 cents at 101.675 cents per pound.

In other news, samples of milk collected from sick dairy cattle in Kansas and Texas tested positive for avian flu, but the nation's milk supply is safe, the USDA said.

(Reporting by Tom Polansek)