I asked my vet this question also and he said that giving a dog antibiotics before mating him will not cause any problems but if you are unsure then to take the dog off the antibiotics 72 hours before the male and female are put together. He also said that some males if natually bred are put on antibiotics to stop him transferring any bacteria to the female. Here my biggest worry is giving heartworm prevention and I do not give heart worm to my female for 3 months prior to mating. Many vet recommend not to give breeding stock heartworm prevention ever. I would take him off the medication as long as the wound does not look inflammed or has puss. If your going to use him over a 3 day period keep him off the medication and then give him the remaining tablets afterwards. I gave my female and male antibiotics one month before mating this time just gone due to 2 phantom pregnancies and she carried 11 pups. Hope this helped and good Luck Lynn