We supplement them...with hay, not purchased protein.
I agree, that if you are grazing in the winter, cows need more
protein...and they need it to help digest the dried grass.
But if you raise hay, and feed hay, purchasing supplemental
protein is rarely needed. We've done many, many forage
tests on the hay for us and customers--and we've done it for
years. Only one time did we find hay that was too low in protein.
In her third trimester a cow requires 2 lbs. of crude protein.
At 10% protein, 25 lbs. of hay with 10% moisture makes the
crude protein 2.2 lbs. At 30 lbs. as fed they would be getting
2.7 lbs. of crude protein. So many times we find too much
protein, as in feeding 20% alfalfa hay. That can be an overkill.
What we are short of in this country is energy.
When it's cold and windy here in the winter, a cow can't eat enough
to meet her requirements. So she should be in a body score
of 6 going into the winter.
OOPS, gotta run, be back later.