My milkers get several different individual feed stuff - they do their own mixing... Dampened sugar beet shreds, rolled oats, a general calf-type mix and cattle dairy nuts. The latter two only when milking or growing. Plus seaweed granules if and when I remember (some love it others don't), also always have either some readigrass or alfa a on hand esp during winter or early lactation. Pony carrots cut into sticks during autumn/winter, branches during summer.
You can feed any cattle feed to goats (better for the extra copper in it), and it is usually cheaper than proper goat mix, though ingredients will be very similar.