I use it year round on my TB. Through the winter he gets it in addition to calm and condition and a conditioning chaff it just gives him that extra 'oomph' and I think help keeps the weight on him.....its so much cheaper than blu chip etc.
Through the summer he just gets the lo cal and chaff. He always looks well and since being on it his crappy TB feet have improved *slightly*
Use it all year round - helps when feeding suppliments in the summer with hi fi light - my mare only has to look at grass and is huge - feeding it now for 3rd summer - really pleased and very economical