HELENA – The state Department of Livestock says a yearling bison heifer on Ted Turner’s Flying D ranch has died after being exposed to naturally occurring anthrax.State veterinarian Marty Zaluski says the bison was found dead Monday near a pasture where the disease killed 287 bison two years ago. The pasture has been quarantined and the ranch is monitoring the herd.Zaluski says it’s not likely the ranch will see a repeat of the 2008 outbreak, which lasted three weeks. He says most of the bison in the 2,500-head herd have been vaccinated against anthrax at least once since 2008. The dead bison had not been vaccinated due to its young age.Anthrax is caused by a the bacteria Bacillus anthracis. Spores of the bacteria can lie dormant in the soil for decades and can become active when heavy rains follow drought. Email Stay Connected with the Daily Roundup. Sign up for our newsletter and get the best of the Beacon delivered every day to your inbox.