Ok, i know that i asked this before, But i have a friend that is breeding her American bulldog... She has never bred this dog before and she is 23 months old i believe she said, Ummmm The male that she is breeding with , is not locking.... He gets it done, but there is no lock.... I know that my neighbour had the same prob, and there was no pups, but she breed only once, My friend bred for 3 days straight.. I have heard of "slip mating" but i need to know what you guys think... any advice will be awesome!!!! Thanks