my Labrador is not able to stand on his hind legs ?

Labs often have hip dysplasia and arthritis (when they get older). Lying in the cold and damp stiffened up his joints and muscles. Take him to the vet for an exam and x-rays. He may prescribe Rimadyl for the pain and inflammation. Also, he'll probably recommend glucosamine/ chondroitin pills and keeping the dog warm and dry.

You can also get or make one of these to help him get up and walk:

http://www.handicappedpets.com/leggings/leggings.h...

Don't know why rain would do that. Had it happen gradually to a doberman once. Turned out it was a harmless calcium growth on the spinal cord which paralyzed his back legs. The growth could not be removed. If it doesn't go away within a day, I'd be running to the vet.

If he is over 7 years old he could have arthritis in his hips, Labradors are prone to getting it. If he seems to be in pain you should take him to a vet.

That happened to my cocker, it was a ruptured disc.. have no idea how it happened.. I was able to get her walking again with meds from the vet, and using a towel to hold her up to force her to use the legs as much as possible...but she was never the same, we had to put her to sleep, she was always hurting after that and would lose bladder control.

TAKE THE DOG TO THE VET IMMEDIATELY. It sounds like your dog has either hurt himself when out in the rain, has arthritis, or possible hip displaces. He needs to be checked out by a professional so if there is something wrong they can treat it. injuries can be healed, the other two things need constant meds.

If it has come on suddenly and he has come in from the rain it is likely to be paralysis caused by a tick, especially if he is lethargic. You need to take him to a vet immediately. The paralysis gradually moves up from the legs until it causes respiratory failure.

It sounds to me like he may be having a spell of arthritis. You didn't mention how old your dog is, but large-breed dogs are prone to problems in their hips (dysplasia) and back. Please contact your veterinarian and explain the problem... for the price of an office visit, you can get your dog some medication which will help ease his joint pain and inflammation. I hope this helps! But please do this soon... it's probably only going to get worse and it CAN'T be comfortable for him. Best of luck to you!

Labs and shepards are know to have bad rear hips, get a vet to x-ray.(even happens to young dogs of this breed)

Go to the vet TODAY!

This could also be a neurological event if he took a fall while outside..

maybe he got hurt or he ran to long he sure slept a long while i would get him to the vet and find out what is wrong with him good luck