Reasons why back legs giveout - Page 1

One cannot make ANY determination about whether the dog has good hips or otherwise simply by looking at him. X-rays are required to determine whether hips are dysplastic or otherwise. So bad hips are NOT out of the question. That is the first thing you must understand. 

Secondly, whether the dog was exhausted, had cramps, an electrolyte imbalance, was having a special kind of seizure is not possible to even speculate without having more information or having observed the dog. It is possible that it was nothing serious, especially since he has now been able to get up again. But I would be very careful with the dog and wait until he has been properly fed, properly conditioned etc., before allowing him to just be running and running. I will say that there are a lot of possibilities here, so being careful with him for now seems to be the most reasonable path. If this happens again, or you note other issues, perhaps a good checkup at the vet is warranted.

Good luck with him.

thank you for your reply.  His hips have been X-rayed and graded Good by O.F.A

thank you for your reply.  His hips have been X-rayed and graded Good by O.F.A

 OK, thanks for the clarification. Good luck.

General lack of excerise i would think if the dog has been confined from doing that for any period of time the Muscles what it has is not been used to using, so there fore cramp may set in it is what is known as Lactic Acid, once the blood is contaminated, lactic acid sets in and the subject can no long run etc that applies to all living things and the part to be affected most is where the dog gets its power from its back legs, Best to work the dog slowly by short walks for a few weeks and build it up slowly, otherwise you can damage if pushed to fast and allowed free exercise
Steve1

Can you even imagine the feeling of running with the wind in your face and flowing thru your hair, after being cooped up for so long. What a feeling for him!

Maybe he collasped out of sheer enjoyment of his new found freedom!  Just ran & ran till he couldn't stand it anymore.  Seriously though, Steve's suggestion has merit.  Like Hodie said, keep him under control until you have him conditioned.  Maybe a little road work, gradually working up to a stronger dog.  Thanks for taking in a rescue!
Deb