dog poops on bed

Question
can you tell me why my 3 year old brittany spaniel might poop on my bed!!!  she is let out frequently during the day, so I doubt its the need to go, and it was not the consistency of being ill or an emergency.  Also, she sleeps on our bed and I thought dogs wont poop where they sleep....She appears in good health, gets all her regular check ups, I dont get it, and dont want to get it again!

thanks

Answer
Sincere apologies for the delayed response.  

There are a few possible reasons for something like his to occur in a normally housetrained pet. If you were not present to witness the occurrence these things would be a bit difficult to diagnose, however might give you something to look for in the future.

If she experienced a seizure it would be very likely for her to defecate during that seizure episode.  If she was frightened by something (phone ringing, storm, doorbell) she could do so in reaction to stress.  These events could repeat but would be relatively unpredictable as she would have to experience the event while again on your bed.  And any other time she could seem perfectly normal.

In the event of some neurological or muscular problem that causes incontinence, I would expect that you would notice abnormalities other times, not just by finding the one accident on your bed.  This is why one my initial thought is towards the above.

If you find this is a recurring problem I would suggest bringing her to your veterinarian for a full examination.  I hope this helps.  Best of luck to you and your canine companion.