i could see wanting to use a rough/smooth collie over border collie based on energy levels alone. a lot of the time border collie lurchers still have ridiculous energy levels. or if you wanted a bigger lurchers, since bcs are much smaller than collies. bunch of possible reasons shrug emoji
i think so much of this depends on why someone want’s this mix/why it was produced. in these days most bc lurchers are bred for sports purposes, popular in agility, flyball, disc dog. all sports that you benefit from having a small/medium sized high energy dog. so why a large medium energy dog? why does that dog need to be a collie/borzoi mix? @snoots-and-whiskers brought up that borzoi was originally introduced into collies to establish breed type, specifically in the head piece, not because people were interested in the workability of a collie/borzoi lurcher, and also mentioned a collie/whippet cross as a lower energy sports prospect which I think could work. I assume using working line collies, you will still end up with a fast medium sized dog biddable enough for sports work but with less energy than a border whippet.(but also aren’t silken windhounds a thing for pretty much this exact reason?) If someone wants a large lurcher for coursing why not just get a borzoi? Why add collie? It’s not like borzoi are untrainable as is, or you need to add collie to tone them down in energy enough to warrant the risk of loosing speed and drive. And for hunting? Most collies have virtually no prey drive, and why cross two fairly rare breeds to make an experimental cross for hunting purposes when there are so so so many proven crosses that are big, cheap, and readily available? And if someone’s does want a large medium energy dog for sports, like agility, why not just get a borzoi? Or look at other breeds? It’s not like traits of speed, medium energy, and trainability are exclusive to herding dogs and sighthounds. I think it’s important to think critically about the breeds being used in crosses, even if the intention is just to create a companion. Like I said in my tags, if there’s someone out there who knows what they’re doing, who wants to create this mix, power to them. With out careful planning, you could just make a huge, fast, tangle of anxiety. And if you do succeed in breeding a stable dog with all the best trait of both breeds you still just sort have an answer to a non existent problem. Does the world really collie/borzoi cross? What niche does this cross fill that’s not already full? Not saying there’s no value to the concept of a smooth/rough collie lurcher, or borzoi being used to create lurchers, or even that a collie/borzoi mix couldn’t be a dog with a nice temperament and working potential. I just think it requires more thought than “that would be cool” because throwing shit at the wall to see if it sticks is part of what encourages backyard breeders to keep making designer mixes that no one needs. Sorry this got long and I hope it doesn’t come off as condescending, I wrote it on mobile so it’s hard to proofread