The cold weather slows weight gain and forces feedlots to keep the animals longer before they're ready to sell to a slaughterhouse. Other grain and soybean prices also rose. Corn jumped upward from the opening bell amid the brightened outlook for U.S. exports over the holiday season. The rally came after agricultural officials from the United States and Japan agreed to test American corn-feed exports for presence of StarLink, a genetically altered biotech corn banned in Japan. The Japanese government will send inspectors to the United States to monitor the tests.
Japan is by far the United States' biggest customer for corn.
But shipments have declined after reports in October by a Japanese consumer group that StarLink was found in snacks and animal feed there. Soybeans rose briefly to a three-month high before losing some of the gains. Wheat futures rebounded from Friday's decline on perceptions the market was oversold.