Today, nutritionists increasingly recognize that the solution isn’t more protein—it’s the right balance of nitrogen sources. Switching to amino acid-focused ration formulation allows us to “narrow the road,” delivering only what the cow needs and reducing waste in the process. Commonly, this can result in decreased crude protein of around 2 percentage units.
Technical Services Specialist
Balchem Animal Nutrition & Health
Precision feeding has rapidly gained momentum across the dairy industry as producers face rising pressure to improve efficiency, reduce environmental impact, and maximize the genetic potential of modern cows. While the concept is simple—provide each cow exactly what she needs and nothing more—the execution on a high performing dairy can be complex. A few starting points to begin precision feeding and improve efficiency include different rations for each stage of lactation and parity, improving feeder training and nutrient analysis of feed ingredients to avoid having to formulate for excess nutrients, ensuring data-driven decisions based on milk meters, behavior and rumination collars, and strategic supplementation of vital nutrients required for high producing, feed efficient dairy cows. This article will focus on strategic supplementation, specifically of amino acids. In this way, nutritionists can narrow the gap between theoretical models and on-farm reality.
IMPORTANCE OF AMINO ACIDS
Amino acids (AA) are the fundamental building blocks of protein, supporting a wide array of biological functions. Specifically for dairy cows, AA can support production of milk and milk components. Though milk protein and fat are vital for the milk check, AA can also support lactose production, and since lactose is the primary osmoregulatory molecule in the mammary gland, it dictates milk volume. When cows receive the correct AA required for protein, fat, and lactose synthesis, they can more effectively convert feed into milk and milk component yields. It is also important to note that AA influence not only milk protein, fat, and lactose synthesis, but also immune function, reproduction, and tissue growth.
FROM CRUDE PROTEIN TO PRECISION NUTRITION
Historically, protein nutrition centered around simply feeding more protein. High crude protein (CP) diets were common because they offered a wide safety margin—essentially a broad road intended to cover all possible amino acid requirements, especially given feed variability. But this approach has critical flaws:
• Deficiency of some essential amino acids
• Oversupply of some amino acids
• Metabolic energy costs associated with excreting excess nitrogen due to oversupply
• Lost production potential due to imbalanced AA supply
The result? Inefficient nitrogen use, unnecessary feed costs, and suboptimal performance.
Today, nutritionists increasingly recognize that the solution isn’t more protein—it’s the right balance of nitrogen sources. Switching to amino acid-focused ration formulation allows us to “narrow the road,” delivering only what the cow needs and reducing waste in the process. Commonly, this can result in decreased CP of around 2 percentage units. This creates a more efficient cow.
Dairy cows require ten essential amino acids (EAA) but methionine and lysine consistently rise to the top as most limiting for milk and milk protein synthesis. Histidine often follows, depending on the diet and production system. Emphasis is often placed on lysine, methionine, and histidine for this reason; however, all EAA are required and must either be produced by microbial protein in the rumen or consumed by the cow. For that reason, it is vital to assess all EAA that are within the metabolizable protein portion, since this would encompass AA that bypass the rumen and AA contributed from microbial protein.
Currently, only rumen protected methionine (RPM) and rumen protected lysine (RPL) are widely available in commercial forms, making them the primary amino acids that can be reliably supplemented in precision rations. Even with high quality protein ingredients, reaching ideal methionine and lysine through feedstuffs alone is difficult—making rumen protected products essential nutritional tools. Utilizing rumen-protected AA such as AminoShure™-XM (Balchem Corporation, Montvale, NJ; 38% metabolizable methionine) and AminoShure™-L (Balchem Corporation, Montvale, NJ; 24.3% metabolizable lysine) allows for a consistent and reliable source of metabolizable methionine and lysine. Additionally, using a range of protein ingredients improves the overall AA profile and reduces dependency on any single feed ingredient’s inherent variability. This strategy is more likely to provide a comprehensive supply of all EAA and meet the needs of the rumen. Rumen protected AA can then be used to “fine tune” the final balance.
To test this concept, a study at Cornell University designed multiple rations with varying AA supply. Comparing a ration with adequate methionine but inadequate metabolizable protein to a ration with adequate methionine, metabolizable protein, and EAA, energy-corrected milk was 1.6 kg greater in the ration adequate for methionine, metabolizable protein, and EAA (Higgs et al., 2022). This indicates that it is not sufficient to only add in rumen-protected methionine, but instead to have a comprehensive supply of all EAA. Though it is important to note there was a 1.3 kg increase in energy-corrected milk yield when methionine was adequate compared to the base ration that was only adequate in metabolizable energy and was inadequate in metabolizable protein, methionine, and rumen nitrogen. This indicates that there can be a small response when only RPM is added, but a larger response when all metabolizable EAA are adequately supplied, alongside rumen nitrogen.
CONCLUSION
Precision nutrition represents a powerful opportunity for dairy producers striving for efficiency, sustainability, and optimized performance. Central to this approach is shifting from crude protein-centric feeding to amino acid based formulation, especially through targeted use of rumen protected lysine and methionine.
As data technologies advance, ingredient analysis becomes more refined, and nutritional models continue to evolve, the industry will continue moving toward a future where every nutrient counts and every cow receives precisely what she needs to thrive and more fully express her genetic potential.
Reference
Higgs, R. J., L. E. Chase, C. G. Schwab, B. Sloan, D. Luchini, P. A. LaPierre, M. E. Van Amburgh. 2023. Balancing dairy cattle diets for rumen nitrogen and methionine or all essential amino acids relative to metabolizable energy. J Dairy Sci. 106:1826-1836.
About Dr. Laura Niehues
Living in the United States in Florida, Dr. Laura Niehues obtained her Bachelors degree in Animal Science from University of Florida and went on to complete a Masters in Equine Nutrition from Kansas State University and a PhD in Dairy Cow Nutrition from University of Illinois. During her PhD, Niehues focused on amino acids during the transition period of dairy cows, specifically rumen-protected lysine. After completing her PhD, she worked as a Technical Services Manager for Novita, working specifically with bypass protein for dairy cows, and for Native Microbials working with rumen microbes and on farm technical support. Currently, Laura Niehues is the Technical Services Specialist for the Eastern United States and Canada at Balchem. She greatly enjoys providing technical support for balancing for amino acids in modern dairy cow rations.
