Most of the products that I recommend are made and sold by my favorite company for supplements, Nature's Farmacy. Here is the link to Nature's Farmacy: Nature's Farmacy. I appreciate your using my link as I earn points to go towards my own supplements for referrals. I've been recommending and using Nature's Farmacy for years without points. Their customer service folks are extremely helpful and their products are extremely high quality. Scroll to the bottom for a complete list of recommended products.
There are several supplements that I recommend that you have on hand. The two most important supplements for a puppy's first year are glucosamine and probiotics. The others I think are good to have on hand for when you need them.
Glucosamine is important as it helps with joint repair from every day wear and tear from normal puppy play. I use Dogzymes Bone and Joint Support from Nature's Farmacy.
Probiotics help with digestion and they boost the immune system. If you don't want to give probiotics daily, I think keeping them on hand for when a dog is on antibiotics, when under any type of stress, or when changing foods is important. I give probiotics daily to all my puppies from the day they are born. I use Dogzymes Probiotic Max from Nature's Farmacy.
Another supplement that I like to have on hand is Vitamin-C. I have done extensive research on vitamin-c and though I am aware that dogs do produce their own vitamin-c, I also know that at times when they are stressed or there is a slight injury (and puppies are so clumsy that they are always falling and slipping and sliding) or especially if they are sick, they do not produce enough. I use vitamin-C if I am working a dog as for obedience or agility or if a dog will be going to a place where he/she might be exposed to sick dogs. I use Dogzymes Super-C from Nature's Farmacy.
Fourth, I put one tablespoons apple cider vinegar in the food for all adult dogs' food and one half TBS for puppies under six months. The best kind is the organic with the “mother” still in it. Braggs makes a good one. But if you have trouble finding it, any apple cider vinegar is better than nothing. I put water in my dogs food because they tend to eat too fast and it slows them down some. The water dilutes the vinegar. Apple Cider Vinegar serves to slightly raise PH slightly which makes an animal less attractive to fleas (and mosquitoes). If you are using natural methods for flea prevention, apple cider vinegar should be a key part of your program.
I also like to use some sort of omega-3 oils or coconut oil. It helps to keep their coats shiny and is good for their general health. Coconut oil has a long list of health benefits but I personally like to rotate my oils. I put either a tablespoon coconut oil or a tablespoon of fish oil. Any coconut oil is fine. If your dog will eat a pill out of his food, a people fish oil pill is fine. These are the 2 fish oils that I currently have and recommend. I like both the Grizzly salmon oil as well as the grizzly pollock oil. I’ve done a lot of fish oil research and found there is a big difference in the quality of fish oils and the amount of omega-3’s in them. I like the Grizzly Salmon Oil and the Alaskan Naturals Wild Salmon Oil.
I use a multi-vitamin when I feed a combination home cooked food and dog food. Though it is probably not necessary, I want to make sure that I am not missing anything. I use Nature's Farmacy Dogzymes Complete. The recommendation is for 1 tsp per 30 pounds of dog but I generally half that because I only feed half or less of my dog’s total calories as homemade food. Again, you probably don’t need if you will be feeding a high-quality balanced dog food but if you decide to go the homemade or raw route, I recommend these vitamins to make sure you’re covered.
A final supplement that I use is an alternative to bone meal. This is only necessary if you are feeding a diet that has cooked food. Calcium is already in dog food in some form and if feeding raw, dogs get a lot of calcium from the bones. But if you cook the meat, you don’t feed the bones as they are brittle and can damage their digestive systems so their diet would be low in calcium. You can get bone meal from Nature's Farmacy.
Here is a complete list of products that I like to get from Nature's Farmacy. If you want to keep your purchase to a minimum, I especially recommend the first two.
Dogzymes Bone and Joint Support
Dogzymes Probiotic Max
Dogzymes Super C
Dogzymes Bone Builder (only if you are feeding a home-cooked meal without bones)