When you look at Eurasian hogs in their own region, you will see what I call a "more tannish hue" overall. Or you will see a "Bluish" hue overall.
Tipped hairs can be a sign of out crossing but to what??? A red Duroc bred to a black female? A couple generations later of mostly black genes and the black can take back over.
With Eurasian crosses you have to remember that even if the parent was a pure russian, these piglets will be watering down the russian genes if not limited to future breeding with pure russian bloodlines.
So with the very limited population of pure russian DNA donors... and the nearly unlimited number of pigs with anything less than 50% russian genes... You won't get a hog that could pass scientific scrutiny as a "pure eurasian" in our lifetimes if ever.
There are some "indicators" of possible russian bloodlines bred into the feral stock. One is a sneaky little "hybrid tooth"...
http://www.hunting-in-texas.com/learnhogs.htm
Scroll down to the "how old is that pig" to see the tooth.
I have doped up, sewn up, and buried up dogs wrecked by pigs of many colors and sizes... Tooth size be danged, the dog wrecker I worry about is what I call a "teenagger thug punk" sort... Any color but these spanish pigs live up to this real well, about 140-170 pounds not terribly old (hence the teenager), 3/4-1 1/2" teeth... These gems are athletic and know it... they are badazz and they know it and they will turn and fight a dog at the drop of a hat... Their agility and tenacity and downright winning intentions make them badder to me than a 400 pound old warrior hog... He can whoop 'em too but usually he wants to slash the swords and run if possible.
Breed matters naught to me... In fact, if you could keep the eurasian out of the mix, your butchering duty could be easier and tablefare better... We bred these domestic lines for various reason and tuff meat under a thick hide ain't them...
Brent