That duration wasn't included in the preview - it's a really disappointing skill if that's the case.
Also, the way the skill reads is this:
"At the start of combat and every time Genie is wished back into existence, he raises his arms - unleashing a magical pheromone across the battlefield. The potent smell raises the Strength of Genie and his allies by 488 for 12 seconds until the smell dissipates.
Every 4 seconds, a random enemy is transformed into a cow, goat, or chicken for 3 seconds."
That does not make it seem like the transformation only lasts 12 seconds, but rather the str buff only lasts for 12 seconds. Was it intended for both to only do that? Perhaps @DSsven can weigh in.