There are a couple things that could be going on with your old girl. One is certainly senility, especially if she no longer lets you know she needs to go out (I assume she used to?). There are some medications, supplements, and diets that can help with senility. One medication is Anipryl (L-deprenyl) and I have had patients improve when taking it. It is somewhat expensive, but can make a big improvement in quality of life. Your vet should be able to prescribe this.
There is also Prescription Diet B/D (for "brain
" diet). This food is very high in antioxidants and can help with signs of senility as well. The food is 100% guaranteed, so if your dog doesn't like it you can always return it.
There are other antioxidants out on the market that are worth trying--they shouldn't hurt her anyway. One is Neutriks. I have a few patients on it, but haven't really heard if it is helping yet. The chiropractic vet I refer patients to seems to like it.
Besides senility, your dog may also be having arthritis
pain (indicated by the limp) and may be having some difficulty squatting or maintaining a squat long enough to full empty her bowel and/or bladder. It would be worth trying her on an anti-inflammatory medication, like Rimadyl
, and see if that helps. At least with this medication, a response should be seen within a week (the senility ones will all take several weeks before any improvement is seen).
Finally, there may be something else going on. A urinary tract infection is a possibility, even with no other symptoms. If she is straining frequently because of an infection, she may be pushing out stool, too. So a thorough physical with bloodwork and urinalysis is the very best place to start.