
Normally I would say until day 28, but as the other poster has said who knows after the jab.
When I had a dog to mate my bitch her daughter had just finished her season and was on about day 24, but the dog would have mated her in preference to her Dam who wasn't quite ready.
I waited until he showed no interest in her in the crate then took them on lead together for a couple of days, and then when I was sure he wasn't in the least interested did I let them together under supervision.
Fortunately in a few days he had better things on his mind.