As a dairy producer, it’s important to know what is happening in your dairy’s nutrition program. Common questions related to amino acid balancing include the following.

Primary benefitsof amino acid balancing

The benefits can relate to any or all of the following:

  • Increase in milk volume and percentage increases in components, which allow you to optimize the pounds of protein and butterfat produced
  • Increase in income over feed cost from minimizing the use of expensive, high-protein ration ingredients
  • Increase in feed efficiency: According to the 2001 National Research Council (NRC) Nutrient Requirements of Dairy Cattle, having the correct amino acid ratios can increase milk protein efficiency up to 65 to 70 percent.
  • Increase space in the diet: For example, feeding 10 grams of a rumen-protected lysine product can increase diet space by 0.3 pounds at 2.4 pounds milk per pound of dry matter, particularly important with fresh cows in negative energy balance.
  • Decrease in nitrogen output

Get the most bang for your buck

The greatest response will be seen first in cows from transition to peak milk. During this time, intake is suppressed and the effective use of every extra pound of diet space is vital to restoring positive energy balance. With only 18 to 20 percent of a herd usually in transition-to-peak milk, the remaining 80 percent typically blend out the response in the bulk tank.

Remember, the fetus growing inside the lactating animal relies on amino acids for 50 percent of its glucose needs. This is why we typically don’t show a response in milk flow from late-lactation animals. There is, however, potential for effects in the unborn calf.

The benefits do continue to be realized, though, as all the cows more efficiently meet their amino acid requirements. Amino acids are the building blocks of proteins. Proteins are found in muscle, enzymes, hormones, etc.


These are typical questions and comments producers have about amino acid balancing:

What numbers should I be looking at?

Most ration-balancing software programs agree the appropriate lysine-to-methionine ratio is around 2.85- to 3-to-1. This ratio also is important due to intake control.

Intake is controlled by the oxidation of fuels in the liver. Fuels come from several sources, including excess amino acids. If the supply of either methionine or lysine is insufficient, the excess supply of the other is oxidized. This oxidation releases non-esterified fatty acids, which in turn suppress intake and affect the liver’s ability to produce glucose, the main precursor of milk production.

The grams of lysine and methionine fed will vary with the herd’s production level and the cow’s phase of production. It is common for high-producing cows to be fed approximately 180 grams per day of lysine and 60 grams per day of methionine. However, as we continue to push the limits of milk production, these grams will continue to increase.

If my ration report lists methionine and lysine, can I assumemy nutritionist is balancingfor amino acids?

Most reports generated by ration software do include the lysine and methionine levels in the diet. However, this does not mean your diet is balanced for amino acids. All feedstuffs include methionine and lysine as some portion of the protein makeup. However, this form of methionine and lysine typically cannot bypass the rumen. In addition, other issues common in the feedstuff form of methionine and lysine include:

  • Digestibility
  • Space in the diet: Commercial amino acid products create extra space in the ration that can be filled with fermentable fiber, sugar or other nutrients, which provides flexibility in ration formulation.
  • Consistency: Feed quality varies significantly even though many products today are consistent.
  • Excess amino acids require energy to be broken down, which may compromise milk production.

When milk price is low, I lookfor ways to trim costs. Can I pull rumen-protected amino acids?

During times of low milk prices, producers may be tempted to pull items from their diet. Remember, though, amino acids are essential nutrients and are needed by high-producing dairy cows.

A recently published meta-analysis in the Journal of Dairy Science showed that across 55 methionine publications, the additional income generated was positive, even in years such as 2009. This was calculated using the responses by researchers and the Federal Milk Marketing Order prices. A meta-analysis on lysine will likely show the same positive profit potential regardless of milk price.

Does amino acid balancingalways work?

Yes, amino acid balancing is an important management tool for high-producing herds. Remember, though, that new skills often come with a learning curve and every herd is different.

Should balancing for amino acids not generate the desired response, typically some cardinal violation occurred. For instance, the crude protein wasn’t reduced to 14 to 16 percent. Doing so assures no excess amino acids will diminish the effects of amino acid supplementation.

You might also confirm current herd dynamics. How many cows were later in lactation? How many animals were in their first lactation? First-lactation animals are still growing and are likely to partition extra amino acids to their growth. If amino acid balancing is flagged as not working, dig deeper. Typically, there’s an underlying explanation.

What are the three most important factors when assessing the quality of a rumen-protected amino acid product?

  • Research: Your rumen-protected product should be thoroughly researched by reputable third-party interests such as universities and research institutes.
  • Consistent amino acid levels: The research documentation should show consistent levels of methionine and lysine, rumen bypass, intestinal digestibility and bioavailability.
  • TMR stability: The product should remain stable in the TMR. If a product breaks down before consumption, it will be degraded and gone before reaching the small intestine.

I haven’t balanced for amino acidsor included rumen-protected amino acids up to this point, and my cows have been producing just fine.

All dairy cows get some amount of rumen-bypass amino acids in the form of microbial protein. Microbial protein consists of the rumen microbes that pass out of the rumen and into the small intestine where they are degraded and their nutrients absorbed.

Genetics and facilities have improved, however, and the modern dairy cow has a much greater capacity to produce milk. As a result, we need to nutritionally support her genetic potential. The 2001 NRC states that methionine and lysine are the two most limiting amino acids for milk production.

When supplemented at an approximate 3-to-1 ratio (180 grams lysine to 60 grams methionine) – a level higher than what current feedstuffs can provide – producers have seen increases in milk flow, component production, feed efficiency and income over feed cost. PD

References omitted due to spacebut are available upon request. Click here to email an editor.

Jessica Tekippe