During the short time I had cattle here, the one thing I learned is that unlike horses (who once they have got upset or objected to something are pretty hard to persuade to leave that behind), cattle are quite capable of being adamant they will NOT get into the trailer and then just as soon as you are ready to give up, they saunter on without a care in the world.
so even if it seems like they won't cooperate, don't lose heart cos they probably will!!