Shark cartilage is used for joint/arthritis disorders in dogs and cats -
it could be used in ferrets.  It appears to be very safe.  Other joint
formulations are more purified and include glucosamine and chondroitin
sulfate - I prefer these supplements myself - I believe they work the best.
The nutraceuticals (like these joint supplement and other herbal things)
are not regulated like regular drugs are and so not all brands are going
to be as effective.  The brand I use on dogs and cats is called Cosequin -
it is also marketed as a human formulation called Cosamine.  I personally
believe it is the best formulation.  You do have to be patient in using
one of the joint formulas - it can take 4 - 6 weeks of using it to see an
improvement.
 
K. Ball DVM
[Posted in FML issue 3313]