I have seen before, most birddogs are what we used to call "limber Tail", dogs a stressed and even on point will not raise their tails, even if they usually have merry way, with the tail up, running. These are the lucky ones. Causes to this becoming more frequent or down and out, is usually Hypoglecima or diabetes. This can be caused by eating something adverse, bad water with algae bloom. eating crayons, dehydration, all are possible. All blood will be normal, thats why the dog recovers! It's like taking a car that won't start to a mechanic, when the mechanic gets it, it starts for him, can't find the problem, the vet or the mechanic has to be there when the symptom is presence. Its hard to get a fix on the problem. With labs they have endemically heart issues, I believe its calls CIM, other dogs may have it, there is a test. This is a high stress reactor, and the dog is down, lathered with sweat, shakey, eyes rolled up, virtually not reactive to stimula. I would give small high grade nutrition to both may times a day working, even candy bars, keep hydrated, use electrolites before excercise. If there is an incident, get a blanket, ( dogs are like old people, they get cold even when its hot), shelter the eyes if they are exposed, secure the tongue, use cold water to bath and try to get food or electrolites inside. Most will respond positively, the CIM labradors will be fine in minutes. There is no practical cure, just mangement.
