Norma Lacey of Grewei Weimaraners uses this from

Natural Health For Pets a book she is finding very useful!

HEALTHY POWDER

2 cups nutritional (torula) yeast

1 cup lecithin granules

¼ cup kelp powder

1 tablespn Dolomite powder

1 teaspn vitamin C (ground) or

¼ teaspn sodium ascorbate (optional)

Mix all ingredients together in a container and refrigerate.

2-3 teaspn per day (I only use 1 teaspn)

Yeast is rich in B vitamins, iron and other nutrients: lecithin for linoleic acid, choline and inositrol, which help your animal emulsify and absorb fats, improving the condition of its coat and digestion: powdered kelp  for iodine and trace minerals: enough calcium to balance the high phosphorus levels in yeast and lecithin (this enables you to add this powder in any reasonable quantity to any receipe or other diet and vitamin C (not officially required for dogs because they synthesize their own, but clinical experiences suggest its value)