To me it looks like filler, and not much more. And the test pretty much confirms that, correct? I thought it was going to be a trick post where it looks poor but tests really high. But it doesn't.
I don't know much about hay, but 5.9% protein sounds awfully low to me.
This seems like something where I would give my horse a flake of alfalfa, and then throw some of this in so they would have something to nibble on throughout the day. (Which is exactly what I do with the bermuda here in AZ). But to give them this and nothing else? I dunno. I don't think you could get by giving this to foals and broodmares, could you? As the only hay I mean?
It looks like lower quality bermuda, but I am thinking what I call lower quality bermuda would test higher than this. At least in protein.
(Again, I will be the first to admit I don't know a thing about growing hay. I'm just giving you my impression as a horse owner.)
So yeah, I guess I am an Arizona girl, and we all feed alfalfa (because it's hard to get anything else but alfalfa and bermuda) and this doesn't look like something I would feed unless it was cheap and I could mix it with my alfalfa.
(But grass hay is the most expensive hay to get in Arizona.)