[souffle]

They don't tend to change in personality or temperament after mating and they don't need a rest period either. I wouldn't tend to overuse any particular male though as you don't want too much crossing of the same genes. Males can be used up to quite an old age and I have used them over 2 years old on first matings with success. With older males you do have time to assess their temperaments and how they mature.
I have heard of the occasional male though who has died not long after mating as it just was too much for him.
They do tend to be much more aware of females in heat after mating and try to get to them and act up a bit when they smell new females. Kept in the same area as females they can lose weight and condition.