For the glucosamine sulfate and glucosamine HCL, chondroitin, manganese supplement, I purchase this in liquid form at the local tack store. It tells you on the bottle how muc to give. For my Rottweiler she gets 40cc and my Newfoundland's I give 50-60cc, my Dobe gets 35cc. For the Astragalus I buy this at my local holistic health store for humans. I give each one capsole daily, I also take 3 a day myself...especially during cold & flu season. The Alfalfa I purchase capsole form at the heath food store and give a capsole daily until I run out then I don't give them any for a few weeks. Kelp, I buy a big container at the tack store at a reasonable price and give a spoonful every 2 or 3 days. I experiment with different herbs for my dogs, I do a google seach and read up on different ones, for instance Yucca I use as an anti inflammatory, slippery elm I use for digestive problems and I forgot to mention I give dandelion root quite often for good healthy digestive system. For my older dog I give her Milk Thistle for her liver this helps support an aging liver and is also great for a dog on anti inflammatories or medications. I make sure they get Yogurt (organic with live bacteria cultures).
The only supplement I make sure they get on a regular basis is the glucosamine sulfate and glucosamine HCL, chondroitin, , manganese and for my older girls I make sure they get Yucca root.
The other supplements I give in moderation and some times not daily unless they are suffering from a health problem and I want something to support their system during that stressful time.
There are some wonderful books you can order which I have found to be wonderful guide lines.
"All you ever wanted to know about herbs for pets" by by Mary L. Wulff-Tilford & Gregory L. Tilford
Here is a page for ordering different books
http://www.sitstay.com/store/books/index.shtml
this book is under Health and fitness. also check under Diet and nutrition for some great books as well.