
That may have been mine and really you need to check the data sheets on anything prescribed carefully and remind the Vet the bitch is in whelp.
I had to use a less strong AB, and my girl ended up with a very stubborn infection after the pups were gone as obviously the AB's hadn't cleared it when she was in whelp. Took weeks and weeks including ear syringing under GA (cost £535 to clear it).
Cannot comment on Thornit as don't know what it is made of.