Is it a bad idea to go mudding with these tires?

Okay so I have a 100 series land cruiser (has a 4.7L V8 DOHC if this matters at all), and I have a grille guard but I am sure this doesn't matter. Anyway I have these basic "Utility Tires" by Bridgestone that aren't really meant for off roading, although they are snow and ice rated. I go mudding now and then, is it a bad idea to mud with these tires? I plan on getting A/T's (all terrains) soon. Thanks