Bulldoze is a decent option on it. However, I would not suggest it, it doesn't need to cover Fire. If a Fire type comes in, you run for the hills with Ferrothorn, not stay in and fight and certainly faint. The Speed lowering lends it a supporting option, but Thunder Wave does that for you and it doesn't work well with Gyro Ball. Bulldoze is a decent choice if you don't have these moves due to hitting five types for super-effective damage. Ingame is likely where it will be the most useful.