Dairy Cow Nutrition

Dairy Cow Nutrition


Precision dairy cow nutrition is key to optimal milk production

Dairy cows require adequate energy and precise nutrition to produce milk at optimal levels of performance. For maximum performance, the milk-producing cow requires different nutrition at different stages of lactation. When in lactation, cows’ diets should provide adequate levels of:

  1. Water, higher than what cows normally require.
  2. Energy, to provide cows with the calories they need for regular function as well as lactation.
  3. Macronutrients (proteins, carbohydrates and fats) and micronutrients (vitamins and minerals). More detailed information about lactating cows’ needs for water, energy and nutrients can be found at Dairy Feed Information & Planning.
  4. Proper balance of amino acids.

Without properly balancing amino acids in a cow’s ration, higher energy levels — and even increased levels of macronutrients like protein — will not result in greater performance in either milk yield, milk components or efficiency.

In fact, when rations lack adequate amino acids, or when the cow is unable to utilize them, one of two results occur:

  1. The cow needs to consume more feed to make up for a nutritional deficiency. Ultimately for the farmer, this means more profit lost on feed.
  2. Alternatively, the undernourished cow produces less milk and milk components, which also leads to reduced milk efficiency and lost profit.

In either scenario, the solution is to properly balance amino acids in a cow’s feed in a way that she can metabolize and use them. Properly balancing amino acids, supplementing the limiting amino acids (such as lysine, methionine and occasionally histidine), can improve milk efficiency and income over feed cost.

AjiPro®-L can supply consistent, stable metabolizable lysine as part of dairy diet to maximize profit.

Amino acid balance: “Barrel theory” in nutrition

Balancing amino acids in a dairy cow’s diet is not as straightforward as increasing all essential amino acids available in the ration. “Barrel theory” in nutrition science describes this balancing act. There are 10 essential amino acids for dairy cows that represent 10 staves forming a “barrel.” The graphics below depict barrel theory for swine nutrition.

The volume that the barrel can hold depends on the shortest stave, because one short stave in a barrel would allow its contents to pour out. In the same way, a cow’s ability to synthesize necessary protein relies on its shortest, or least available, amino acid.

Barrel theory is also called limiting amino acid theory, because the amino acid in lowest supply limits the amount of protein the dairy cow can synthesize.

Importance of lysine

Of the 10 essential amino acids dairy cows need, the first two limiting amino acids are lysine and methionine, because common feeds such as corn and corn silage are relatively low in these amino acids compared to what dairy cows need for milk production.

Dairy cows do not create their own lysine, so farmers and nutritionists may add various ingredients to cows’ feed in order to meet the lysine requirement for high-producing dairy cows. Unfortunately, some portion of the lysine in these feed ingredients is broken down by bacteria and other microorganisms in the rumen. This can make it difficult to predict the amount of lysine that actually reaches the small intestine where it is absorbed. As a result, even with some lysine supplementation, the lysine available to the cow is often at levels below the cow’s requirement.

Why balance amino acids in dairy rations?

Amino acid balancing helps:

  1. Optimize milk production.
  2. Decrease nitrogen excretion by the dairy cow.
  3. Improve income over feed cost by minimizing the use of expensive, high-protein ingredients.

Amino acid balancing and income over feed cost

The study results represented in the table below describe how milk efficiency improves with amino acid balancing:

In the same study, even though an amino acid balanced diet cost $0.24/cow/day more than the control, the increased 5lbs of milk production generated $0.65/cow/day profit net increase — even at low milk price $13/cwt. The figures below demonstrate the relationship between amino acid balancing and overall profitability:

Despite depressed milk prices, amino acid and balancing leads to higher profitability.


AjiPro®-L Trials


AjiPro®-L sets the standard for supplemental rumen protected lysine. It is a highly bypassable, digestible and available source of L-Lysine for the high-producing dairy cow. When properly formulated into a ration, AjiPro®-L delivers a predictable amount of lysine for absorption by the cow and improves the overall balance of amino acids in the diet. AjiPro®-L is a cost-effective source of rumen protected lysine with the high level of protection and consistency you expect from Ajinomoto.