This is Zap Apple, the oldest daughter of Applejack and Rara/Coloratura. Her special talent is understanding zap apples -she can sort of feel when they are about to come, without having to rely on timeberwolves, and is very good at figuring out recipes (aka. which colvoluted steps to take) to make different zap apple products.
 
The reason she lost her leg is because she’s often the first one out to check on the zap apple trees as they are approaching harvest, and one time she was a bit too eager. She’d gone in the middle of the night, without waking anyone else, and ran right into a pack of timberwolves who’d also sensed the signs. That was a long time ago, but she’s still terrified of the everfree forest and wolves/dogs; the only one she can be around without panicking is Winona the fourth.
 
The “headband” she’s wearing is designed and created by Twilight; it reads the impulses of her brain, allowing her to control her prosthetic leg. It is technically only in the experimental stage, there only being a few protoypes made, but Zap Apple trusts Twilight and asked to be allowed to act as a test-subject for it. She’s gotten quite used to spending afternoons hooked up to different scanners in Twilight’s basement, as her aunt frantically checks to make sure she’s not frying her brain or something.
 

 
I actually really like designing next-gens, and I do have a few which I am trying to decide if I should draw properly and post. They will need some redesigning though, a few are a bit… old (or, How-could-I-ever-think-those-colors-looked-good).
 
I really like Zap Apple’s design (even if her name leaves something to be desired); I like thick/floofy tails and manes, and I think the colors turned out pretty cute. I started by just trying to find what looked good, fit the character, and seemed like it could be inherited from her parents. Then I realized that her colors at the time were pretty close to how zap apple trees look, and the rest sort of fit into place