i think [bANNED TEXT] ever you have u gotta chuck that bit of pure back in every now and then judging the dog you breed from weather it being you put a saluki or a greyhound back because like some one said some of these line breeds get abit slow so if that me i would chuck a greyhound back across or if the dog maybe a bit racy or or lack bit of stamina i would chuck saluki back or abit of 1 st cross is the way to be pure helps if you no how your dog is breed and you judge the running style right. just my opinion