I am not used to figuring silage, but everything is figured on a dry matter basis, because moisture contains no nutrition.
So here is what I came up with:
40# silage@35% DM (65% moisture)=14#DM x 8% Protein=1.12# Protein
17# grass (I gave it 12% moisture-just a guess)=14.9#DM x 7% protein (halfway between 5 and 9%)=1.04# Protein
5# Alfalfa (again I figured 12% moisture)=4.4# DM x 17% protein=.748# protein
Your total DM (Dry matter) is 14 + 14.9 + 4.4 =33.3# Good!
Total Protein is 1.12 + 1.04 + .748 =2.9# Protein (higher than needed in second trimester. Maybe try 3# of alfalfa, but at the price you are getting the alfalfa, I'd just give then the 5# as fed.
You have plenty of protein, but we are guessing here, better to be too high as not enough.
This ration more than meets the the requirements at 20 degree temperature. The lower the temperature and if the cattle are wet, the more the requirements.
Energy is important, but I have no way of figuring that unless I know the TDN. With that much protein, my guess would be the energy would be okay.
If the moisture is more than I have guessed, then that throws everything out of whack. Most hay in our country is 10-12% moisture, so that is a 'book value' more or less and what I used. Can you get the moisture content of the alfalfa and/or the grass hay? It would be interesting to know if hay in that area is higher in moisture than in our country.
I like the rfv being 125 in the $65/ton hay. More value for your money IMO. That hay here would be at least twice that.
Since I don't know about silage, I'm open to comments. Feel free.