The soft poo tells you her " tanks" are full, so to speak. Then it's maintenance. Alfalfa is high in calcium. To arrive at a 2:1 ratio of Ca:Mg, as Verona posted, you'll need a lot of supplemental magnesium.
Feed XL will tell you if it's still low with what Vita Plus provides. If yes, supplement it.
Same with ration balancers. I feed Nutrena Empower Balance. No magnesium added. Here, soil lacks mg. So my hay has next to nothing. So I have to supplement.
To get an idea of what the different hays contain, on average, over a number of years, go to equi-analytical or dairy one. They test thousands of samples every year. Pretty interesting, actually, especially if analyzing your hay doesn't make sense because it's coming from different suppliers.