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Enhancing Dairy Profitability and Sustainability: Germany’s New Protein Evaluation System and the Power of Methionine

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The dairy industry is at a crossroads. Environmental pressures are mounting to reduce nitrogen excretion and minimize the ecological footprint of milk production. At the same time, economic realities demand that dairy producers find ways to optimize feed costs and maximize the efficiency of their herds. In response to these challenges, Germany has introduced a new protein evaluation system that promises to reshape how nutritionists formulate diets for dairy cows. This system–coupled with strategic methionine supplementation–offers a powerful way to enhance profitability while driving sustainability.

From Utilizable Protein to Digestible Protein

For decades, the dairy industry in Germany has relied on the “utilizable protein” system to assess cow protein requirements and utilization. While this system served its purpose, it had limitations in accurately accounting for the complex processes within the cow’s digestive tract. Germany’s new approach, centered on “small intestinal digestible protein,” marks a shift in dairy nutrition.

Dr. Karl-Heinz Südekum, Professor Emeritus of Animal Nutrition at the University of Bonn and a key architect of the new system, explained the fundamental change in a recent webinar hosted by NOVUS (watch the webinar).

Südekum explained that the small intestinal digestible protein system focuses on the total amino acids that reach the small intestine and their digestibility rather than just the protein content of the feed. This variable allows nutritionists to tailor diets more precisely to the specific needs of each cow.

“We are convinced that this will contribute largely to an improvement of nitrogen use efficiency because a more tailored supply of individual amino acids is possible,” he said.

By considering individual amino acids, nutritionists can better match the supply of these essential building blocks with the cow’s requirements for milk production, growth, and maintenance. This targeted approach optimizes protein utilization and minimizes excess protein that can contribute to nitrogen excretion and environmental pollution.

The Unsung Hero of Ruminant Nutrition

The new German system also places a greater emphasis on the role of microbial protein. Microbes in the cow’s rumen ferment feed and produce protein, a crucial source of amino acids for the cow.

“We looked at the microbial part of amino acids and the protein that flows into the small intestine,” said Dr. Südekum. “The first question was: what does the amino acid pattern of microbial protein look like? And why should we address this topic [when] there’s already data based on a meta-analysis that shows the amino acid pattern of microbial crude protein?”

Researchers conducted a new analysis specifically focusing on typical Central European rations, which contain a maximum of 60% concentrates in their total diet. They also differentiated analyzers of fluid- and particle-associated bacteria plus protozoa, pooled data of bacterial fractions, and estimated protozoal contribution to total microbial amino acid flow to the duodenum.

By understanding and accounting for microbial protein, nutritionists can refine feed formulations further, ensuring that cows receive the right balance of amino acids from both dietary and microbial sources. This approach improves nitrogen efficiency and reduces the need for protein supplements.

“The quality and flexibility of the new systems will contribute to improved nitrogen use efficiency during the production of milk and meat …” said Dr. Südekum. “The major driver (demonstrating) that the system serves better than the previous one, in terms of nitrogen use efficiency, is the improved correction of the feed protein value.”

The new protein evaluation system is included in the German “Blue Book,” which also includes updated recommendations on energy evaluation (switching to metabolizable energy), structural value of rations, feed and water intake, and mineral requirements. This comprehensive resource provides nutritionists with a wealth of information on optimizing dairy cow diets. Dr. Südekum said the Blue Book is being translated into English and will be available later this year.

Methionine: The Essential Amino Acid for Dairy Success

While the new protein evaluation system provides a powerful framework for optimizing protein nutrition, one amino acid stands out as particularly crucial: methionine. Methionine is the first limiting amino acid in most dairy rations, meaning it is often the first to become deficient. This essential nutrient is critical in milk protein synthesis, metabolism, and reproduction.

“Balancing diets to meet cow’s requirements on methionine ensures optimal health, milk production, and reproductive performance,” explained Edwin Westreicher, Dr. sc. agr. habil., NOVUS Technical Service Manager Dairy – EMEA, during the webinar. “We also are concerned with environmental problems related to nitrogen excretion. The most efficient strategy is reducing crude protein content in diets.”

Lowering crude protein content is a common way to improve nitrogen efficiency, lower nitrogen excretion, and lower feed costs. However, this practice can inadvertently lead to methionine deficiency. This is where strategic methionine supplementation becomes a game-changer.

NOVUS’ MHA® Feed Additive

MHA® Feed Additive is a unique methionine source designed to support dairy cow performance and producer sustainability goals. Created with the HMTBa molecule (hydroxy analogue of methionine), it provides a dual mode of action that sets it apart:

  1. Source of Metabolizable Methionine: It is efficiently absorbed and converted into L-methionine within the cow, providing a readily available source for milk protein synthesis and other essential metabolic functions.
  2. Rumen Modifier: It acts as a rumen modifier, enhancing ruminal fermentation and the biohydrogenation of dietary fatty acids for milk fat production, especially during seasons of milk fat depression3.

“MHA® Feed Additive offers 84% methionine equivalent and contains 33.6% metabolizable methionine with no additional nitrogen1,” Westreicher said. “The remaining methionine acts as a rumen modifier, supporting fermentation and milk fat production. This makes MHA® an incredibly efficient and sustainable way to supplement methionine without increasing nitrogen excretion.”

Methionine in Action

MHA® Feed Additive has demonstrated its value in real-world dairy operations, offering a range of benefits across different stages of production:

  • Milk Production: It is absorbed through the rumen, omasum, and lower gastrointestinal tract for the animal to use for milk protein production.
  • Transition Cows: When a transition cow lacks methionine supplementation, the hepatic lipid metabolism can be limited, affecting dry matter intake near and post-calving, which will take longer to reach peak lactation. Cows supplemented with MHA® produced an average of 3 kilograms more milk than cows without supplementation (control) over 84 days2.
  • Milk Fat Depression: Milk fat depression is characterized by a decrease in milk fat yield of up to 50% with no change in milk yield or yield of other milk components. It is observed in ruminants fed highly fermentable carbohydrates, diets high in plant oils, or under grazing conditions. The latter diet conditions cause changes in rumen biohydrogenation of unsaturated fatty acids that subsequently reduce milk fat synthesis in the mammary gland. MHA® Feed Additive optimizes ruminal fermentation by supplying the microorganisms with available methionine to maintain the diversity of rumen microflora and help sustain normal rumen biohydrogenation and increase the milk fat content under milk fat depression conditions3.
  • Economic and Environmental Sustainability: This feed additive supports dairy operations’ economic and environmental sustainability efforts through greater nitrogen efficiency and lower nitrogen excretion.

The Future of Dairy Nutrition

Germany’s new protein evaluation system, coupled with strategic methionine supplementation using products like MHA® Feed Additive, represents a significant advancement in dairy nutrition. These tools empower nutritionists and producers to formulate more precise and efficient diets, ultimately leading to healthier cows, higher milk production, and improved sustainability. As the dairy industry evolves, embracing these innovations will be crucial for long-term success.



1 Feng, X., R.R. White, H.A. Tucker, M.D. Hanigan. 2018. Meta-analysis of 2-hydroxy-4-methylthio-butanoic acid supplementation on ruminal fermentation, milk production, and nutrient digestibility. J. Dairy Sci. 101: 7182-7189.

2 Piepenbrink, M. S., A. L. Marr, M. R. Waldron, W. R. Butler, T. R. Overton, M. Vázquez-Añón, and M. D. Holt. 2004. Feeding 2-hydroxy-4-(methylthio)-butanoic acid to periparturient dairy cows improves milk production but not hepatic metabolism. J. Dairy Sci. 87:1071–1084.

3 Pitta, D.W., N. Indugu, B. Vecchiarelli, M. Hennessy, M. Baldin, and K.J. Harvatine. 2020. Effect of 2-hydroxy-4-(methylthio) butanoate (HMTBa) supplementation on rumen bacterial populations in dairy cows when exposed to diets with risk for milk fat depression. J. Dairy Sci. 103:2718-2730. DOI: 10.3168/jds.2019-17389



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