First off, welcome to the site. FYI, calling a Sarplaninac a "Sarplaninac mountain dog" is redundant. The name actually means "dog from Sar mountain, or Sar mountain dog." Secondly, what was your socialization protocol? 6 weeks is actually a good time to start socializing a pup to livestock. Most has been said here before, but my fear is that her genetics and possible upbringing mistakes may have made efforts too late, though who knows, there may be hope. Correct me if I am wrong, is she around a year? Did she start exhibiting this behavior at 6 months? This is typical for adolescents and this chasing should have been curbed then. The longer any undesired behavior has to manifest, the harder it is to curb. I noticed you said she leaves the goats alone, lol. Well not surprising, they fight back, lol. I hope some of this helps, though without being there, it is hard to give sound advise. I would contact someone in your area with more experience for help. Coppinger did some studies involving LGD behavior and the genetics behind it. He would place LGD (mostly Sars) and herder pups together to be raised to see if there was any cross influence between the herding behavior of the Colies. He actually discovered that the prey response is not inhibited, yet delayed, so imprinting of the behavior is "curbed" but not eradicated. This gives LGDs a good "prey drive" just different. Very interesting study, you should look into it. I can give you the info if you are interested. That being said, not curbing behavior at certain points is detrimental to further work, and makes things harder. Are you in the Northeast? Maybe YL can help if in your area. Though she has COs, she has a good understanding of flock and LGD interaction and could help you problem shoot. If you are out west, I have a few other people that might help. :)