D.A.P. vs. Feliway?

I just got to thinking, how is D.A.P.(Dog appeasing Pheromone) different from Feliway? I mean, the D.A.P. is for dogs & Feliway for cats, but are the pheromones used different?

I want to pick up some Feliway spray Thursday when I can get it. I was thinking that when I run out, a vet clinic near me carries D.A.P. spray. If it works the same, then I could use that. If not, I'll be sure to order more spray when the bottle gets lows.