Czar, I suggest that you get some generic vitamins and gauge what you need for your dogs. Prenatal vitamins are water-soluble so whatever your dogs don't use, they pass through urine. I use them on myself when I am getting ready for a powerlifting competition. An old man put me on to them a long time ago. Just be careful with whatever you use because some vitamins are toxic when too much is given. JMHO