Why not use Glucosamine for dogs? There are specific products that are for dogs only. I use it for my 3 yr old Golden Retriever who has arthritis does wonders for her and much better to give due to the smaller sized tablets.
I buy it in a 90 tablet bottle but can also get in 250 tablets (Beef Flavoured). I get the Aristopet Brand bought from pet supply stores but you may want to ring them up before you go there as they dont all have them. Some pet shops sell them also.
They do have a webite but the product is not shown there. So you can just email them for stockists nearest to you.
www.aristopet.com.au
If you want to get their email address just go to contact us on their website.
Good Luck with it anyway.