One second they were munching contentedly, as bovines do, in a field that had been providing sustenance for at least 15 years. An instant later they were convulsing, bellowing and dying as ranchers looked on helplessly. Over the next few hours, 15 of the 18 cattle died.
The mystery was only partly solved with the revelation that they had been poisoned with cyanide—manufactured by the grass itself. That’s what investigators determined after analyzing the Tifton 85 grass, a Bermuda hybrid (not genetically modified, as was originally reported), CBS News reported on June 23. The grass was producing cyanide gas.
"A lot of leaf, it's good grass, tested high for protein—it should have been perfect," rancher Jerry Abel told KEYE, the Austin-based CBS affiliate that first reported the tragedy.
What happened next was anything but.
"When our trainer first heard the bellowing, he thought our pregnant heifer may be having a calf or something," Abel told the local television station. "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."
Investigators are still trying to figure out what made the grass go rogue—whether it was associated with ongoing drought, or a sudden mutation—and testing grass elsewhere in the vicinity, which also is producing the gas, though it has not killed any cattle.
A hybrid is produced by the blending of two or more varieties of a plant in a practice that has been used for centuries. It is different than the controversial genetic modification method of creating breeds. U.S. officials are checking for random mutations of this grass variety, CBS News said. The variety has been in use since the 1980s, and rancher Jerry Abel had used it for 15 years, he told investigators.