Source: <a href="http://www.cbsnews.com/8301-201_162-57459357/gm-grass-linked-to-texas-cattle-deaths/&feed_id=1&videoid=37&catid=57459357">CBS News</a>
A genetically-modified form of Bermuda grass known as Tifton 85 mysteriously started producing cyanide.
"When our trainer first heard the bellowing, he thought our pregnant heifer may be having a calf or something," said Abel. "But when he got down here, virtually all of the steers and heifers were on the ground. Some were already dead, and the others were already in convulsions."
Within hours, 15 of the 18 cattle were dead.