Lab/Pointer cross tail down

Question
My lab/pointer cross has had his tail down for about a day now, he still wags it, eats, runs and plays and overall seems okay other than the tail down.  Could it be a sprain? Constipation? Can I give him a baby aspirin 81 mg?  He is about 50 pounds.  Any other suggestions?

Answer
This is not an uncommon thing at all. There are many reasons why this happens- bumping their sacrum, running up stairs too fast or down them, or even spraining the muscles around the tail head.

You might want to press gently around the area and see if he quivers like it hurts. It would be a good idea to look under his tail also to make sure he doesn't have a wound that is getting fly-blown. Gross I know but it happens in summer and that can make him keep his tail down.

You can give one aspirin per 30 lbs of body weight. Go easy because it is very harmful to the stomach.
If he doesn't feel better in a day or two then get him into the vet's.