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Precision nutrition for calves: Moving beyond crude protein concentration in milk replacer

for Progressive Dairyman Published on 04 May 2018

In the current economic climate, dairy farmers are looking to increase efficiency across their business and reduce costs. Although it is viewed as a small portion of the dairy enterprise, nearly 20 percent of the production costs incurred on a dairy are attributed to raising replacement heifers.

Of that number, just over 15 percent of the total cost of raising a heifer comes from the first two months of life. This may seem like a small fraction of the heifer program but, as farms get larger and margins get smaller, precision is needed in calf programs. One way to improve precision is to look at calf nutrition.



Precision in calf nutrition starts with understanding which nutrients limit growth. Most commercial milk replacers in the U.S. are scrutinized based on how much protein and fat they contain. However, calves do not have dietary requirements for protein or fat.

Specific building blocks provided by the diet, including amino acids and fatty acids, are what calves need from milk or replacer, as the liquid diet is the sole source of nutrition in the first few weeks of life.

And as the industry moves away from traditional 1-gallon-per-day feeding rates, greater amino acid intakes are required to increase growth rates. University and feed industry studies have shown increasing protein concentrations in milk replacer increase growth rates.

However, there is always a plateau in growth rates around 26 to 28 percent protein, indicating diets over 26 percent protein result in less nutrient retention and, therefore, more nutrients wasted by the calf.

The concept of ideal proteins and balancing diets using synthetic amino acids have allowed the poultry and swine industries to improve feed efficiency, reduce wasted nutrients and minimize feed costs. Even dairy nutritionists formulate cow diets to optimize metabolizable amino acids supplied for maximum protein efficiency, milk yield and reduced environmental impact. However, calf nutrition is just now catching up with balancing milk replacers for essential amino acids.


Let’s start at the beginning and think of what nature intended a young dairy calf to consume. Whole milk protein includes two major fractions, caseins and whey proteins. As casein is sought by dairy processors predominantly for cheese production, this leaves whey as a byproduct for use in other manufacturing.

Commercial milk replacers typically include mostly whey proteins, as they are low-cost, high-quality milk-based ingredients. However, very little casein makes it into milk replacer formulas due to its value in cheese production. Because the biological value of whole-milk protein is ideal for young calf growth, commercial milk replacers need ingredients to recreate the ideal amino acid profile without adding excessive cost.

This is where synthetic amino acids can play an effective role in improving growth and efficiency in the milk feeding period.

Commercial milk replacers in the last five years have focused more on providing synthetic lysine and methionine thanks to research showing repeatable and cost-effective improvements in performance. Studies from the Nurture Research Center have consistently reported greater than 10 percent improvement in calf growth in milk replacer formulas ranging from 20 to 28 percent crude protein when using synthetic amino acids.

By including synthetic amino acids, we can have identical growth rates feeding a 24 percent crude protein milk replacer compared to a 28 percent crude protein milk replacer that is not balanced for amino acids (Figure 1).

Average daily gain from 0 to 4 weeks of age


This translates to significant cost savings for the farmer as the bag price, even when including synthetic amino acids, will typically decrease about $2 for every unit of crude protein pulled out of a formula. If we can replace up to four units of protein in a milk replacer, that can translate to a substantial $8 savings per 50-pound bag or a 24-cent savings per calf per day for a 1.5-pound milk replacer feeding rate.  end mark

Tana Dennis
  • Tana Dennis

  • Calf and Heifer Nutritionist
  • Provimi North America
  • Email Tana Dennis

Take-home points

  1. Calves are most efficient when their diet contains all the necessary building blocks for health and growth.

  2. Balancing milk replacers using synthetic amino acids improves calf growth at least 10 percent consistently when compared to unbalanced milk replacers with identical crude protein content.

  3. Precision nutrition using amino acids can replace at least two units of crude protein in a formula,
    saving $4 or more per bag of all-milk protein milk replacer.

  4. To determine if your milk replacer contains synthetic amino acids, look for specific amino acids in the list of ingredients on the feed tag and ask your supplier for research data supporting their use in their milk replacers.