By Tom Polansek CHICAGO (Reuters) – Farmers in Florida rushed to reach their cattle on Thursday after trees downed by Hurricane Ian broke fences used to contain the animals and rain from the fierce storm flooded fields used for grazing. One of the mightiest storms to hit the U.S. mainland in recent years, Ian flooded communities on the Gulf Coast before plowing across the peninsula to the Atlantic seaboard. The hurricane washed out roads, hampering farmers’ attempts to corral cattle before they escape fenced areas in a potential threat to public safety. “We’ve got trees all over the fence line…