I have two heifers that both need their hooves trimmed, but I have heard that if you put them on a table to trim hooves they can lose their calf. They are both about 4 months along and are going to the fair in about a month.
Depends on your trimmer, they all have different opinions, ours will do it right up to calving, we used another that wouldn't trim feet after I think 6 months.
If your trimmer won't they have no business being around cattle. We trim every dairy cow 0-60 days pre-calving on a tilt table mounted on a truck. Have for years. Never had a problem only concern I ever have is with a wild one that works herself up. But maybe I'm just blessed as I have seen this question asked before. My hoof trimmer is one of the greats, we had a cow get all jacked up and banged her front leg up while he was getting her to the chute. He has called every 3-4 days since it happened to make sure she was ok. Use common sense and you will be fine.