It's been a long time since I've posted here (I usually just lurk), so I'll start with some background. We adopted Livi from rescue when she was 3-4 months old. Her mother was a Border Collie from somewhere in rural Texas, and her father was a traveling man. The neighbor's Aussie was mentioned as a possibility, but as she's grown up all I see is Border Collie. Livi and her brother ended up in a shelter when the owner didn't find homes for them, and from there to rescue. They went through a mild bout of what was believed to be parvo (they were supposedly vaccinated, but tested positive for parvo). The rescue saw them through and kept them long enough to be sure they were completely recovered and off all medication. Since we've had Livi she's been healthy. She's 2 years old this summer. Until February we lived in a suburban neighborhood so although she did get regular exercise, it was somewhat limited. Playing in the backyard, running around weekly or so in the field where we took training classes, and we had started a couch to 5k program together (very light running on leash... really just trotting for her). In February we moved to a place on 14 acres, which means Livi has a lot more room to run and explore. She's in and out with me wherever I go, and of course if I'm walking out to the barn she's running every which way along my general trajectory.
Wednesday evening, we went for our usual walk down to the river and back around sunset. It's a little less than half a mile if you follow the path; quite a bit more the way Livi does it. She was running around as usual, and when we got back near the house she started staggering a little and her rear end seemed floppy. She mostly stayed on her feet, but if she tried to turn much at all her back legs would sort of fail to follow and go out from under her. We got her back in the house where she had water and cool tile to lie on, and she was fine. When I saw it I immediately thought of what I'd read here about Border Collie Collapse. I looked at older threads and watched a few videos and that looks exactly like what was happening.
We haven't taken her to the vet yet since she recovered so quickly and completely and we have what seems to be a very likely explanation for what happened and no useful treatment for it -- but should we, to rule anything else out? I'd thought we'd see if it happens again and I can get a video. I don't want to neglect medical treatment if it's needed, but if there's no real reason to go in I'd rather not. (This isn't "just a dog" thinking -- I'm the same way with my kids).
I'm also trying to think about what to do going forward, if this is BCC. The exercise that presumably led to her collapse was just her accompanying us on a walk. There was no encouragement or pressure for her to run as much or as fast as she did -- she did it because she wanted to, and she loves it. I can put her on a leash to prevent her from running, but that seems like overkill. Maybe I can let her run halfway and then put her on a leash the other half to reduce the length of her exercise. But it seems like with BCC, I can't just let her self-regulate as I've always done. She does generally reach a point where she slows down -- loses interest in chasing a ball or frisbee, or just walks along with us rather than running every which way. She'd keep going if I encouraged her, I'm sure, but since she's not working or anything there's no reason for her to continue past the point of enjoyment. I'd had thoughts of doing agility with her when we got her, but now that we live out here she seems to get the exercise and mental stimulation she wants and I'm happy with that. We walk around sunset, so it's still hot (Texas in June), but we try not to be out much in the real heat of the day. I haven't found it terribly oppressive yet this year... but I've lived here all my life, so heat is just a way of life.
I'm also wondering if I should suggest the rescue mention this to the person who adopted her brother just so they're aware. Again, I thought I might wait to see if there's another episode or if this was just a fluke, but given that it seems to be genetic it seems like it might be worth passing along.
I suspect what needs to be said has already been said in the older threads I read, but I just wanted to post in case anyone has advice, particularly on management, or even just to mention it in case it helps someone else.