Yes, you can give glucosamine/chondroitin to animals. The doses, gosh darn, I had written somewhere, but not sure. Sorry. But you can find that on the internet. I also have the dose breakdown for herbs.
I started using Celedrin for particular problem of mine and liked it better than glucosamine/chondroitin. So I started giving it to the boys and they actually improved.
I don't use walmart brands. I chose not to. I usually stick to brands like Jarrow, Source Naturals, etc. Only because i checked into it and liked what I found.
Some good products exist for our doggie friends out there you may want to do a search and find a product you can buy in bulk and sprinkle on the food.
Using glucosamine/chondroitin is also used in conjunction with MSM. It takes about three or more months though to see any difference. I did find the celedrin worked faster. About 7 years ago a friend with arthritis told me about the celedrin and I checked into the studies on it. It seemed reliable source so i tried it out. So you may want to check into this doing your own research. Its pretty interesting. It was gentle enough that my husband who had luekemia was also taking it.
You may also want to check into bromelain and other anti-inflammatory herbs. Watch the combinations that some companies use though. Their mixtures don't make sense and really won't be effective. You can always look up the monograph of an herb. Also you can visit different pet herb sites and gather as much info as you can. Then you can also double check on this site:
Veterinary Institute of Integrative Medicine
They have some good links you can follow through on.
And don't forget the omega's. Some good fish oil also helps. I prefer Alaskan Sockeye oil, but there are many different types out there. Try to avoid farmed fish oil. Find out where the source of the oil is from.
The Monterey Bay puts out great information on seafood and how its caught.
Seafood Watch Program | A Consumer's Guide to Sustainable Seafood | Monterey Bay Aquarium
Just things you want to watch for for quality.
Have fun!
Wanderingherb