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Amino acids: A complex concept with profound results

Elliot Block Published on 19 November 2009
Amino acids are the building blocks of protein, a fundamental nutrient required for optimal cow performance and health. While they are the simplest elements of protein, balancing diets for these amino acids is a very complex concept.

Nutritionist Dr. Marty Faldet with GPS Dairy Consulting, LLC knows just how critical amino acid balancing can be for peak performance in the milking string. With 19 years of experience as a nutritionist in the Midwest, Faldet began balancing rations for amino acids three years ago after learning about its benefits at industry meetings.

“Looking at protein levels and nitrogen excretion had become a new area of focus. Amino acid balancing provided some opportunities to make improvements in both these areas,” explains Faldet. Faldet researched the practice and identified the value when diets properly deliver key limiting amino acids.



While any amino acid can be limiting, those termed essential – meaning the cow cannot readily synthesize them in sufficient quantities – are usually the ones that are most limiting. Frequently, the two most limiting amino acids are lysine and methionine.

When properly delivered to the ration between practical and optimal levels – 6.8 to 7.2 percent lysine and 2.25 to 2.4 percent methionine as a percentage of metabolizable protein, respectively – the milk and component production results can be astounding.

Turning research into practice
Before reformulating diets, Faldet approached his dairy clients about the amino acid balancing concept and the value that could be realized. The benefits of amino acid balancing included improved milk and component production and reduced ration protein levels.

Faldet shares that in many cases ration costs did increase, but protein quality also improved. Even with higher costs, the improvement in income over feed cost outweighed the investment. Faldet says he’s found value in amino acid balancing since he first implemented the practice, but has seen the greatest value over the past 16 months. Amino acid balancing has helped many of his producer clients to maximize profit margins.

“Many of my dairy clients have been able to capture higher financial rewards during this past year, which has offered some solutions during these especially challenging times,” shares Faldet. Real-world amino acid balancing success stories This past summer one of Faldet’s dairies was seeing herd milk protein levels at 2.87 percent, which was disappointingly below previous levels. The dairy turned to Faldet for suggestions on how they could regain higher milk protein levels to achieve optimal profits.


“I revisited ration formulation with a direct focus on boosting lysine and methionine to optimal levels,” he explains. Ration changes were made in late July, and a one-tenth protein percentage response was seen within a few weeks. By October, protein levels had climbed to 3.12 percent.

“We were really pleased with the response we saw in milk protein production,” says Faldet. “While ration costs did increase, the additional pounds of protein increased the milk check more than the ration increase cost.”

When lysine and methionine are supplied at optimal levels, the animal will use their protein with as much as 10 percent greater efficiency. This allows for a diet formulation with less total protein.

Making adjustments for long-term success
While the benefits of amino acids have been confirmed through experience similar to Faldet’s, there are challenges that accompany proper amino acid supplementation. Variability, says Faldet, is one of the largest challenges he faces when balancing diets for amino acids.

While multiple bypass methionine feed ingredients exist, a cost-effective rumen bypass lysine has not always been available. Research shows commodity lysine sources – like blood meal – are extremely variable in lysine and protein availability, which means every load should be tested to ensure the ration is properly balanced for amino acids. The study confirms great variability can be seen depending on where the feeds come from.

“One of my main frustrations is that sometimes results are more quickly seen on one dairy and not another, and identifying what’s different between the rations can be challenging.” Even with its challenges, Faldet believes the opportunities seen with amino acid balancing far surpass the struggles he faces.


“I believe amino acid balancing allows producers to have their cake and eat it too. In the past we have sacrificed milk production for components, or components to jump production levels. With amino acid balancing, we’re able to maximize both.” PD

References omitted but are available upon request at