If a bitch has had problems conceiving or had an infection after her last litter I might advise to swab, but generally I don't like giving antibiotics unless really necessary.
Or do you mean ovulation testing?
I don't do that either
but I do know people who have, and spent a fortune swabbing every 2 or 3 days, and STILL not got a mating , or a mating with no pups!
I do know people who have had success with the Draminski and Mate Tell.
But haven't used them myself.
Thinking of sending Skye back to Zaz in the autumn but kennels owner insists all bitches are swabbed on 2nd day of season, doesn't really bother me but the thought of two 10 hour round trips again is making me quiver already LOL!