Don't take the dog with you, go in and assess its reaction to you. If it turns to face you and doesn't turn away, proceed with caution. If it shakes its head at you, retire. If it paws the ground, retire.
Look underneath - if smooth, it's female

. If not, if you can look at it from behind it will be fairly obvious if it's a bull.

Most cattle do not want a confrontation and will move away from a human who approaches them. There's no calf to protect.
Bulls on their own may be more likely to stand their ground, but it's a beef breed so as long as you don't go in screaming like a banshee and waving flags at it, it will probably be prepared to move away gracefully provided you don't make it feel like it's losing face to do so.
If you aren't comfortable, see if you can get a pic or two and post on here. If you have a good camera you may be able to get a shot of the eartag number.