Blood meal is a popular source of lysine. But research conducted by Marshall Stern, ruminant nutritionist at the University of Minnesota, indicates that blood meal can be a very inconsistent product.

Stern looked at four different samples of blood meal, comparing lysine percentage, percent rumen undegradable protein, percent lysine digestibility and percent metabolizable protein in the lysine.

Percent lysine ranged from 8 percent to 9.2 percent; rumen undegradable protein ranged from 80 percent to 95 percent, lysine digestibility ranged from 53 percent to 80 percent, while metabolizable protein in the lysine ranged from 4.21 percent to 5.89 percent.

These variances make it difficult to consistently balance rations for amino acids using blood meal, particularly if the amino acids provided by blood meal vary every day or in every load of blood meal delivered.