Officers arrived to find two members of the public, one a former animal control officer, had found the canine stranded 10 feet down inside the bunker-style silo.
The officers and residents were able to lasso the dog with a rope and pull him to safety.
The dog, a springer spaniel, turned out to be Milo, a pet who had escaped from his home 44 days earlier. The home is located about 20 miles from the grain silo.
The shelter said Milo "survived frigid temps, snow storms, hunger and dehydration." Veterinarians determined he had lost a lot of weight during his time on the loose.
Milo was reunited with his family and "many tears were shed from everyone," the shelter said.