Over the last few decades, ration balancing tools and product development technologies have improved exponentially. We also have a greater understanding of the cow’s biology and dietary needs.

This understanding has led to simple, yet highly effective, nutritional products that enhance animal performance – rumen buffers, protected fats and yeast derivatives – merely being added on top of the existing diet.

These products are known as “feed additives.” But what about more complex product technologies such as rumen-protected amino acids?

Can we simply add them on top and expect acceptable performance? Are they really just “additives” or should we think of them as highly specialized “ingredients”?

A cow’s biology/genetics determines the cow’s potential to produce milk and is always on and available to respond to better nutrition. To fully and efficiently express the cow’s genetics, she needs to consume high-quality nutrients in sufficient quantities to meet her biological requirements.


Meeting these requirements is becoming more difficult as the modern dairy cow’s nutritional requirements increase to meet higher production levels – her ability to physically consume more nutrients has not kept pace.

For example, a Holstein cow on a dairy with an overall herd average of 50 lbs of milk per day has the genetic ability to produce far greater than 50 lbs of milk, even though that may be her current level of production. If the nutrient quality and quantity in her ration was improved to meet her genetic potential, she would respond with better performance.

The dairy cow does not have a protein requirement but rather requires amino acids, from which protein is built. Any protein that is fed to the cow is broken down into amino acids, which are then utilized by the cow to meet her nutrient needs.

In the past, overfeeding protein was a very common approach to meeting the amino acid requirements because protein was relatively inexpensive and environmental excretion of nitrogen was not a big concern. Today, protein quality and price volatility are major concerns, as is the need to reduce nitrogen excretion into the environment.

In 2008, after nearly 10 years in development, the first rumen-protected lysine product hit the market. Today there are several other rumen-protected lysine products available, with varying levels of rumen protection and efficacy. As with most new products, there has been a learning curve to determine the best way to integrate this new technology into dairy rations.

Some believe rumen-protected amino acids should be used as additives to increase milk or milk component production, but this approach produces inconsistent results. Rumen-protected amino acids are nutrients and, as such, have the ability to accentuate the biology of the cow and facilitate the use of other dietary ingredients to better meet the production, health and reproductive needs of the animal at all stages of lactation and levels of production.

They provide nutrients (i.e., lysine and methionine) more efficaciously and consistently than other feedstuffs, such as commodity blood meal and soybean meal, without oversupplying nutrients the cow may not need.

Cows also have a finite intake capacity. When balancing a ration, one of the biggest challenges is to manage that “intake box” to meet the rapidly and continually changing nutrition and economic environment that drives on-farm profitability. These changes are caused by fluctuations in forage quality, purchased ingredient quality, ingredient inventory constraints and many other variables on the farm.

Regardless of the reason for a ration change, the most valuable but limiting factor is usually ration space. Without having flexibility in the ration to make changes, it is nearly impossible both nutritionally and economically to adjust to the rapidly changing conditions that every dairy experiences almost daily.

Perhaps the most important benefit rumen-protected amino acids can provide is through the reduction of the bypass protein fraction, creating much needed space that can be utilized to supply other nutrients such as energy and fiber.

Historically, rumen-protected amino acids have been reserved for premier dairies or situations where a production response is desired. This is most often due to the fact that rumen-protected amino acids were promoted as feed additives similar to yeast products and rumen buffers. As a result, they are typically seen as adding cost to the ration.

However, amino acids are not feed additives. They are required nutrients and should be used no differently than any other feed ingredient contributing required nutrients to the cow.

Feedstuffs have become increasingly more expensive, inconsistent to source and can vary significantly in quality and consistency. As a result, the ability to use rumen-protected amino acids as feed ingredients to supply nutrients in everyday rations becomes more compelling and economically feasible.

Strategies for using rumen- protected amino acids: Substitution or partial replacement

Perhaps the most versatile and optimal use of rumen-protected amino acids in everyday rations is to substitute or partially replace the essential amino acids already being provided by other feed ingredients. In this manner, they are used no differently than any other feedstuff such as soybean meal, blood meal or distillers grains.

Benefits of this approach:

  • Total ration costs can often be reduced
  • Ration space is created to allow for other nutrients (e.g., energy or fiber)
  • Increased consistency of nutrient flow and improved resistance against changing milk and feed prices (i.e., as more ingredients are used in lesser amounts, the impact of the quality and price variability of each ingredient on the total ration is reduced)
  • Increased consistency in supplying nutrients compared to heat-treated ingredients such as blood meal and soybean products
  • Can be used with simple thumb rules and does not necessarily require the use of complicated modeling programs (i.e., remove 0.25 lb of blood meal and replace the lysine difference with an equivalent amount from a rumen-protected lysine product)
  • Can be used with sophisticated computer modeling optimization systems to meet a specific dietary nutrient specification on a best-cost basis

When using rumen-protected amino acids as everyday ingredients, production responses will be dependent upon whether or not the specific suboptimal level of AA was corrected (e.g., improved the ratio of MP-Lys to MP-Met) and/or what nutrients were used to backfill the space created by using them (i.e., was more energy or fiber added to better meet the optimal levels of these nutrients?).

Addressing both of these aspects will allow for a better and more efficient expression of the cow’s genetic potential.

Add-on-top approach to increase the total grams of MP-Lys and MP-Met

The most commonly used approach for feeding rumen-protected amino acids is to add them on top of what is currently being fed to improve the lysine-to-methionine ratio and increase the total grams and concentration of lysine and methionine in the ration. The ultimate goal is increased milk production and components, particularly milk protein.

Benefits of this approach:

  • If the suboptimal level of lysine and methionine is corrected, generally a clear and visible production response can be observed and a return on investment calculated
  • Simple and easy to do
  • As more lysine and methionine are added to the ration, it may allow for a more optimal expression of the cow’s biology, which would allow the cow to maximize her genetic potential

However, there are several drawbacks to consider when using the add-on-top approach. Cost will always increase and, therefore, a performance improvement is required to supply a positive return on investment. Oftentimes this is very difficult to measure in commercial settings. This is due to the many confounding factors prevalent on many commercial dairies.

Determining the optimal levels of lysine and methionine are only as good as the ability to know the lysine and methionine in current feedstuffs and of current modeling programs to predict the cow’s nutrient requirements. These requirements are consequently based on model inputs (e.g., intake, bodyweight, accurate ingredient analyses) and are often not accurate.

As a result, you may add more rumen-protected amino acids than necessary. The success of this approach is also highly dependent upon the nutrient contribution of other dietary ingredients. Additionally, this approach is highly dependent upon other ingredient costs and milk prices.


There are several different ways to utilize rumen-protected amino acids in ration balancing which allow for a better expression of the cow’s biology and optimized genetic potential. Perhaps the easiest and first step is to begin by using rumen-protected amino acids as ration ingredients to improve the overall ration dynamics and animal performance while reducing ration costs.

As you push to make higher-quality milk more efficiently with a smaller impact on the environment, you must contend with ingredients that are often inconsistent in price, quality and availability. The use of rumen-protected amino acids can be a valuable tool to accomplish this goal while creating a higher-quality and more consistent ration. PD

Ryan Ordway
  • Ryan Ordway

  • Nutritionist and Technical Services Specialist
  • Balchem Corporation
  • Email Ryan Ordway