Climbing horse feed?

Hi folks, we have two adjacent pastures hosting our horses. We're thinking about converting the larger one into garden, and planting up the 4-ft fences with (hopefully perennial) climbers. It would be nice if we could dedicate the portion of fence bordering the other pasture to things the horses will enjoy, any suggestions?

Bindweed? That probably doesn't need any encouragement. Maybe you want to go with a less noxious member of the morning glory family and plant sweet potatoes. And if the horses don't like the taste of the vines, you can always dig the tubers in the fall.

My horses enjoy grazing the leaves off my established grapes, and if I time it well there is less pruning for me before as the grapes start getting a good cluster forming .
I am doing a little experiment planting an protecting grape vines to train on cordons just above sheep grazing height at about 4 and 6 feet and in some places this is above where the raspberry canes are planted in the same row . These young grapes are needing protection from the horses for a number of years but eventually and growth that strays within their reach will be grazed off . Eventually my goal is not to feed the horses but have vertical production in border areas with grazing animals such as sheep and geese .

Some of my horses got into the yard and discovered the sweet potato plants...Yummy!