
WAs he doing the ladder climbing (during which time the dog ejaculated the initial portion) as opposed to just thrusting forward which is generally before the dog has penetrated and more about aim.
During the tie the dog ejaculates mostly prostatic fluid, which is a food source for the sperm.
During Semen collection, it is noticeable that there are three fractions to the ejaculate, the first cleans the pipes, the second (the part they aim to store) is the semen rich fraction, and after that mostly prostatic fluid.
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/reprod/semeneval/dog.htmlDogs ejaculate semen as three distinctive fractions. By using a clear plastic collection tube, the delivery of these three fractions is easily monitored.
Pre-sperm fraction: this is usually slightly cloudy in appearance and has a volume of roughly 0.5 to 2 ml.
Sperm-rich fraction: in normal dogs, this fraction is distinctly milky in appearance.
Prostatic fraction: this fraction is recognized as a crystal clear fluid flowing into the tube, and ejaculated slowing over a prolonged period of time. In most cases, collection is stopped as soon as this fraction is recognized.
So yes the slip mating can result in puppies.
Quote: "Most dogs stop thrusting as they begin to ejaculate."