The Frolicking Horse Family Gift Set #7213, included this model, along with a mare (same as set #7211?) and foal. Unknown what year(s) this was released. Was available at Big Lots, and maybe other similar stores.
Set #300712 Playful Horse & Foal, included this model and leopard appaloosa foal. Unknown what years it was available, or what stores, though this looks like a Tractor Supply number. (No Copyright info on box, and no catalog enclosed).
#7037 Cowboy & Rider Set and #300712 Playful Horse & Foal Set have nearly the same color, stockings and blaze. #7037 has a shorter mane and tail and a dorsal stripe. #300712 has a much longer mane (on the opposite side of the neck) and tail and a newer looking paint job.