ELGIN (CBS NEWS) - A mysterious mass death of a herd of cattle has prompted a federal investigation in Central Texas. Preliminary test results are blaming the deaths on the grass the cows were eating when they got sick, reports CBS station KEYE. The cows dropped dead several weeks ago on an 80-acre ranch owned by Jerry Abel in Elgin, just east of Austin.

The grass is a genetically-modified form of Bermuda known as Tifton 85, which has been growing in the area for 15 years, feeding Abel’s 18 head of Corriente cattle. Corriente are used for team roping because of their small size and horns. “When we opened that gate to that fresh grass, they were all very anxious to get to that,” said Abel.

Three weeks ago, the cattle had just been turned out to enjoy the fresh grass, when something went terribly wrong. “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. “That was very traumatic to see, because there was nothing you could do, obviously, they were dying,” said Abel.

Preliminary tests revealed the Tifton 85 grass, which has been here for years, had suddenly started producing cyanide gas, poisoning the cattle. Other farmers have also tested their Tifton 85 grass, and several in Bastrop County have found their fields are also toxic with cyanide. However, no other cattle have died.

Scientists at the U.S. Department of Agriculture are dissecting the grass to determine if there might have been some strange, unexpected mutation.

Also Check Out:

• Lawsuit Filed Against Apple’s Siri Technology
• Storm Cells Trigger Damaging Hail In DFW
• Texas Teen Walking To D.C. With Cross On Back
• Wrong-Way Driver Sets Off Deadly Dallas Pileup
• Family’s Dream Home Turns Into A Nightmare