CHICAGO (AP) _ Grain futures were mostly lower Thursday on the Chicago Board of Trade. Dec. corn was off 2.25 cents at $5.00 a bushel. Dec. wheat lost 3.5 cents at $6.83 a bushel. Dec. oats rose by 8 cents at $4.35 a bushel. Nov. soybeans lost 7.5 cents at $12.87 a bushel. Beef was...