I am breeding my Rottweilers, my female has had two litters previously, my stud dog is new to me but has had three litters with his previous owner. The dogs are hot and heavy, she is completely receptive, they are copulating but not achieving a tie. Everytime he is about to tie she scoots out from under him. Is he ejaculating enough sperm to get her pregnate withour the "tie"?

when dogs tie it is to keep the sperm inside thefemale and cut down on the chances of another dog breeding with her. it should be enough to get her pregnant