A 17 month old colt is coming to our yard next week it will be done the day after!!!! How long should it stay away from the mares. We have a mixed herd.
After castration there won't be much semen left in the ducts, and the chances of them covering a mare and actually making her pregnant are very small. But you will always be advised to keep them away from the ladies just in case.
However, testosterone hangs around in the body for a lot longer, at least a month, so the little chappie will still think he is all man for quite some time. So it's better for both the new gelding (while he is healing) and the mares that he is kept away from the ladies until he forgets that he ever had testicles.
A week is definitely not long enough and the colt could be at greater risk of complications such as haemorrhage if they don't keep him away from mares.
I'd be worried generally to be honest. Clearly the owners haven't done their homework in the veterinary department, and no way would I move a baby to a new home, then subject it what is quite a nasty (and probably painful) op the very next day. Stress and then more stress. Poor baby.