No, it's not difficult, today there are none, we can consider Rep z Pohranicni straze a one of the basis of the breed.
If you know a pure dog without him, please let me know.
Lets see by Kazan (F1) which was made for refresh the blood of the breed.
Kazan was born after, for the opening of the line and, according to database, he was mated with Rep daughter and Rep granddaughter, then, of the 3 litters he had 2 already will have Rep z PS soon at the start, Ada z PS was a linebreeding in Lord z PS without Rep z PS blood, but her B litter, which was another linebreeding in Lord z PS free of Rep z PS were all lost in time, by her A litter you will note that almost all the offsprings mated with dogs which had Rep z PS in his blood, A.Lobos was the last of this line free of Rep z PS, because all the females he mated had Rep z PS in their blood.
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