Milk Production Efficiency with Different Protein Sources

The goal of every dairy ration is to provide the nutrients needed by the cow at the best possible cost.

When nutrients are “balanced” — neither overfed nor underfed — the cow receives the most efficient ration, resulting in the most efficient milk production possible. This is particularly important when it comes to selecting the protein feed ingredients in the ration.

There are a few factors we can consider to help determine which ingredients are most likely to maximize milk production efficiency, including:

  • The cost of the ingredient
  • The cost of the rumen undegraded protein (RUP) of the ingredient
  • The amino acid profile of the RUP fraction of the ingredient

With the amino acid profile, we can determine the “milk protein score” — a measure of protein quality that compares the amino acid composition of protein sources to the amino acid composition of milk protein. Figure 1 below shows the milk protein score of several common protein feed ingredients.

From this figure, we can see that canola meal has the highest milk protein score of the vegetable protein sources. This score provides a quick visualization of the amino acid profile of the RUP fraction of ingredients. While not the complete picture of milk production efficiency, the score can be helpful in selecting protein ingredients.

For even greater accuracy in evaluating the potential value of protein ingredients, the Dairy Feed Calculator tool compares ingredients based on the ingredient cost, digestible RUP, energy and phosphorus.