Yes it's a perfectly fine supplement at less than 6% of total intake and is also a great source of energy. But, you have to feed such a small amount, just like SBM or other high pro feeds, it's better used mixed with corn, oats, wheat or some grain. I like to use some in feeder rations better than cow supplement. Really though the only time it is a valuable feedstuff is when soy is cheap.
Figure a mix of 25% protein mix of soy and grain and feed 5-7 pounds to lactating cows on grass hay.
#All suggestion made in this post, are my own. Not responsible for any loss, just gains
