I've used it for a few years and LOVE it. I have found that the bitches bounces back faster and doesn't seem to lose their coats the way they used to. I give it to them starting when I know they are pregnant and they stay on it until the puppies are weaned.
When the puppies start solid food they get it as well. I continue it with them until 4-6 months.
I have found my puppies go home about 3 pounds heavier but NOT fat. Solid puppies with great growth potential. I'm happy with them!