US | mysterious animal deaths Here's What Killed Those Dead Cows Toxic sweet potatoes were included in their feed By Evann Gastaldo Posted Jan 31, 2011 1:38 PM CST Copied The cows were done in by sweet potatoes. (?karlfrankowski) The latest mass animal death mystery has been solved: The 200 cows that dropped dead in a Wisconsin pasture two weeks ago were killed by, of all things, moldy sweet potatoes. The farmer who owned them originally suspected disease, but investigators ruled that out and determined the cows were likely poisoned by the spoiled sweet potatoes, which were included in their feed, Aol News reports. Click here for more. Read These Next Trump to Bondi: 'I think it's time.' Iran just hit one of the Middle East's largest oil refineries. Special forces reportedly rescue US crew member from Iran. Travelers will likely cheer at this new advice from airports. Report an error