Smarter Protein Feeding for Dairy Cows

Amino acid focused feeding boosts efficiency milk yield and cow health

Protein plays a vital role in milk production, growth, reproduction, and overall health of dairy cows. For many years, dairy rations often included more protein than needed to ensure cows received enough nutrients. Recent research shows that feeding extra protein does not always improve performance and can reduce feed efficiency. 

Protein is made up of amino acids, which contain nitrogen and carbon. True protein provides amino acids, while crude protein includes both amino acids and non protein nitrogen. In dairy diets, what matters most is how well nitrogen can be used by rumen microbes. These microbes are not selective about the nitrogen source as long as it is soluble and degradable. 

“When we talk about protein in dairy diets, we need to consider what the rumen microbes can use,” said Essi Evans, Ph.D., E+E Technical Advisory Services. “The microbes are not particular about whether nitrogen comes from a true protein or non-protein source as long as it’s accessible to them.” 

Rumen microbes use nitrogen to grow and digest fiber, which helps supply energy to the cow. They also produce microbial protein, which provides many of the amino acids cows need. In general, about 8 to 10 percent of ration dry matter becomes microbial protein. The rest of the cow’s amino acid needs must come from feed ingredients. 

“Every gram of excess protein that a cow doesn’t use is a gram she must eliminate,” said Dr. Evans. “That disposal costs energy which could otherwise be used to support milk production.” 

The closer the amino acid balance matches the cow’s needs, the less energy she uses to manage excess or missing nutrients. Amino acid balance can be compared to a puzzle. If the pieces fit correctly, the cow performs efficiently. If there are too many or too few pieces, energy is wasted managing the imbalance instead of producing milk. 

Excess protein must be broken down and removed from the body, which requires energy. Studies show that feeding poorly balanced protein increases maintenance energy use and reduces milk energy output. This means that excess protein directly limits milk production. 

Researchers have explored the idea of an ideal protein, which supplies amino acids in the right proportions with minimal excess. This ideal protein can come from a single ingredient or a combination of feeds. Research comparing common protein sources found that some ingredients align better with cow needs than others. 

In these studies, canola meal and fishmeal were shown to supply amino acids efficiently. Corn protein was less effective, while barley and soybean meal were intermediate. Better aligned protein sources reduce waste and improve energy use. 

Precise feeding is important for modern dairy systems. While meeting protein needs is essential, avoiding overfeeding is equally important. Ration programs may overlook energy losses caused by excess protein, leading to missed opportunities for better milk yield. 

By focusing on amino acid balance and protein quality, dairy producers can improve feed efficiency, support cow health, and increase milk production while reducing nutrient waste. 

Photo Credit: gettyimages-vwalakte