I'm starting to collect seeds and stock to start a J. Russell Smith style farm here in central GA, but I'm having a tough time identifying trees that will work specifically for cattle (and possibly sheep at some point) since his book deals a lot with feeding hogs. Already have persimmon, honeylocust, mayhaw and mulberry as well as a bunch of nut tree stock to furnish human food. What fruits work best with cows? Which trees provide best foliage and respond to grazing pressure? I'm in zone 7b.
Cattle will eat apples. I've seen some of our cattle eat the fallen apples off the ground, (we've had various breeds over the years, mostly holstein). Saving seed from the apples you eat is an inexpensive way to get a few trees if you don't care about the variety.
For forage, poplars and willows. Quality diminishes as the season progresses. There has been a lot of research done on tropical forage trees, many of them nitrogen fixing. Some of them may be appropriate for your area, if allowed by your state ag dept. No one wants another kudzu style invasion. Kudzu was brought in because it is good forage. What works for you will also depend on what your animals find palatable.
Here in Norway (north western Europe) ash,elm and willow were considered among the best fodder trees. Others were also used (birch, rowan). It was common to dry bundles of branches with leaves to store for winter fodder. My cows seemed to prefer the ash leaves over silage or hay in winter.
The term "goat hay" is sometimes used when referring to cut and dried leafy branches of trees collected for winter fodder. Might bring up some hits in a google search.
Generally it seems like allowing your cattle and sheep free access to trees doesn't work so well, but maintaining some pollarded at about 8ft means you can cut fresh branches year on year without it becoming a dangerous job working at height.
Moderator, Treatment Free Beekeepers group on Facebook.