The general dosage recommendation is 1,000 mg. of glucosamine and 800mg of chondroitin per 50lbs. Combination products are available through your veterinarian. Some products have additional Vitamin C added as well. I am currently evaluating other nutritional products for arthritis as well and will keep you informed about those. Antioxidants may also be extremely beneficial in the treatment of arthritis.
Antioxidants are helpful by controlling free radicals which are associated with cartilage damage.
The most readily available antioxidants include Vitamins A, C, and E and the mineral Selenium. Dosage suggestions vary, I usually recommend 2,000 IU of Vitamin per 50lb. Bioflavonoids may also be beneficial since they help make collagen which is a primary component of cartilage. There are many herbs that appear to be beneficial for arthritis as well. This is a whole other story.