Balding back legs

Question
Hi,
I have three female guinea pigs that are currently 5 years old. Recently i have noticed that one of them has balding back legs. The skin and fur is clear and it's just on the outside of her back leg up to her hip. They were all treated for mites a few months ago so is it possible they have come back? I have also read that hair lose can be hormonal or a sign of ovarian cysts. I will be making a vets appointment but i just wanted to get some idea of what it could be.

Thank you.

Answer
You're right on both counts. It could indeed be mites again. Most breeders treat for mites about every other month. So yes, they can and do come back.

However, the area of balding does give the possibility of ovarian cysts. At 5 years old these are considered elderly girls now. The ovarian cysts are fairly common in older females, especially if they've never been bred.

As for what to do for them?  Most likely your vet will say do nothing, and I agree. An expensive surgery for a pig that age will not give you any guarantee that the problem will be solved. Your bank account however, will be considerably smaller.     

These ovarian cysts are rarely malignant, and although they can cause cosmetic issues like the balding legs, they don't really do the pig any true harm.  I would not put a pig of mine through surgery. The possibility of not coming out of the anesthesia is too great.

It would not hurt to treat her again now for mites, but as far as treatment for ovarian cysts you'll need to make that decision with your vet.  If it were my sow I would not risk her life by putting her through the ordeal.