Chicago Board of Trade corn futures fell while soyameal climbed early Thursday after the USDA reported preliminary tests showed an animal tested positive for mad cow disease, traders said. Soyameal prices were supported on renewed prospects that meat and bone meal could be further restricted in feed rations, while corn was pressured on ideas of reduced beef demand. December corn futures were down 1-3/4 cents at $2.04 and December soyameal was up $1.90 at $159.70 per ton by 9:40 am CST.