Go to the vet and get a progesterone test which will pin point peak fertility in a bitch. But if you don't know these things you probally shouldn't be breeding. Or making more pet puppies, dont breed unless you have tested for genetic diseases and have a correct to standard rott. Also don't breed unless you know of people who will actually buy the puppies.

If you dont even know when your dog should be bred, should you really be breeding at all? your rottie will need to be hip scored and eye tested first of all to make sure it is of good breed standard to be bred from before even considering breeding from it! If you do you could end up with dogs with joint problems, bad temprements/inbreeding-hense why researching your dogs lines are ever more inportant-especially with large breed dogs to make sure the sire and dam are compatable.

My simple answer to you my friend is DON'T breed! you obviously do not have a clue what you are doing, and will give genuine reputable rottie breeders a bad name!

good responce