CHICAGO, Aug 26 (Reuters) - Chicago Mercantile Exchange feeder cattle futures declined on Friday as a spike in crop prices signaled higher costs for livestock feed, brokers said.

Grain and soybean futures rallied at the Chicago Board of Trade on concerns that unfavorable heat and dryness in the U.S. Midwest will limit yields in the upcoming autumn harvests.

CME September feeder cattle futures ended down 2.050 cents at 182.200 cents per lb, after rising earlier in the session to their highest since Monday. Most-active October feeders slid 2.125 cents to close at 183.400 cents.

Live cattle futures also weakened, with the October contract settling 0.600 cent lower at 143.050 cents per lb.

Prices for choice cuts of boxed beef fell 78 cents to $262.76 per hundredweight (cwt), the U.S. Department of Agriculture (USDA) said. Select cuts rose $1.22 to $238.76 per cwt.

In the CME hog market, futures were mixed. Most-active October lean hogs settled down 0.450 cent at 90.650 cents per pound, while December hogs rose 0.325 cent to 82.950 cents per pound.

Meatpackers slaughtered an estimated 451,000 hogs on Friday, down from 467,000 hogs a week ago and 463,000 hogs a year earlier, the USDA said. Packers slaughtered an estimated 123,000 cattle, up from 122,000 cattle a week ago and 116,000 cattle a year ago, the agency said. (Reporting by Tom Polansek; Editing by Vinay Dwivedi)