Orchardgrass: persistence versus preference. Some of the grazing trials show that the longevity/persistence is due to less utilization by animals: less preference. Cutting trials only tell a small part. Or plan to reseed with whatever is at the local store to thicken when you see the problems of thinning.
Fescue: pick your poison. KY31 is not a horse type forage and some cattle don't do well. But the effects can be less as hay versus forage. Like it or not, it works as a persistent forage. The novel endophytes types are not all created equal. It only takes a few trials of them to learn the reality. And preference is also an issue if they stay around. Growth amounts are not all very impressive. Some of the selections have been released too soon: my opinion.
Options to fill in the spots and keep yields up: cool season annuals: timothy, brome,... find out what works around you.