Yes....not with Harry (yet!) but with Rosie our Labrador.
She was diagnosed with arthritis when she was about 12 years old, and OUR VET (!!!!) actually suggested we give her a glucosamine + chondroitin supplement daily, which we did, and she lived another 3 years in a far 'easier' condition than she was in previously
She was a big girl though (just like her mama!!!
) so I don't know how you could work out the proportions - worth a try though Michelle?
Sally x