Depending on which diet you feed, you will need to follow the author of that diet's recommended guidelines for supplements. There are tons of prepackaged feeding supplements on the market today. Make yourself familiar with them to help simplify the process. Read the ingredients label to see exactly what is in each supplement, and be sure that you are not overdosing on any one vitamin. You can also go to any health-food store and purchase each supplement separately and add them to your dog's food at each meal. Some common supplements are kelp, alfalfa, vitamin E, vitamin C, cod liver oil, fish body oil, eggs, flaxseed oil, and yogurt.
One supplement that most Golden Retrievers can benefit from is the proper balance of essential fatty acids. EFAs, as they are commonly called, are often present in commercial dog food, but evaporate out of the kibble before you have a chance to feed it to your dog. The essential fatty acids for dogs are a combination of omega acids 3, 6, and 9. Every dog is a little different in the way he uses these fatty acids, but their absence can result in the chronic skin problems so common in the Golden Retriever.
Finding the right balance of fatty acids is essential for healthy skin and coat. These supplements can be found in a prepackaged form in dog supply catalogs and pet stores, or you can go to the local health-food store and purchase them separately. EFAs are extremely heat- and light-sensitive and should be stored in the refrigerator after they are opened. It is important that you do a bit of research by reading a good canine nutrition book (as listed in Appendix A) for the dosage recommendations, and finding the right source of essential fatty acids for your situation.
My dog is overweight. What should I do?
If your dog is overweight, assume the responsibility of taking the weight off of him. A Golden Retriever will literally eat himself to death. Goldens have absolutely no ability to regulate how much food they eat — if left to their own devices, they would literally eat until they exploded. It is entirely up to you as your Golden's guardian to reduce his calorie intake and help him stay lean.