A large (IME) % of people feeding a commercial feed out of a bag say they feed “grain”, regardless of any cereal grain content.
I don’t think of TC SR as grain, I call it feed. Which is generic also but I distinguish it as feed compared to the the alfalfa cubes I give and think of that as forage. I do know what Tc Sr is!
I also don’t take advice for exactly what to feed from posters on the internet. As in anything I do in life, I read all I can find and then make my own decisions. Therefore the reason for asking about books on the subject of Equine Nutrition. I do take that kind of advice
I’m assuming you have already checked out safergrass.org also www.drkellon.com
I have no advice, but am always learning where I can, and hadn’t seen you mention these specifically, so thought I’d throw them out there. Always more to learn…