What milk components can tell you about your herd

The milk check not only provides a lot of information about your herd’s production, components and quality counts, but also gives you insight to monitor health and nutrition.


Healthy butterfat levels can be achieved with the right balance of forages and concentrates in the diet. When rumen bugs break down forage, they produce volatile fatty acids (VFAs). One VFA, butyrate, is used to synthesize half of the fat destined for the udder, which means high-quality forages can dictate butterfat levels.

Low butterfat (<3.0%)

Rations high in energy from grain concentrates often cause low butterfat levels. These feeds bypass the rumen quickly and provide minimal nutrients for the rumen microbes. Adding forage to the ration can slow feeds from quickly passing through the rumen and allow for proper and complete breakdown by rumen bugs to boost VFA levels.

Very high butterfat (>4.0%)

High butterfat levels are often seen shortly after freshening, which can be a sign of ketosis. While this is common in early lactation, monitor this group closely to ensure milk fat levels decline to normal level—between 3.5% and 4.0%—and production levels increase. This shows cows are using energy from the diet, rather than fat reserves, to meet production levels.


The right balance of ration protein and energy is needed to ensure optimal milk protein levels. A fully functioning rumen with a thriving microbial population can provide the essential amino acids and energy needed for enhanced protein production.

Low milk protein (<2.8%)

Rumen bugs convert dietary protein to bacterial protein, which is the primary source of essential amino acids for the cow. Once converted, these amino acids can be used by the mammary gland to produce milk protein. Energy is needed to complete this process and without the proper levels of energy, amino acids are used as the energy source. This can reduce the supply of amino acids for milk protein synthesis.

In some cases, supplemental amino acids are needed to complement those produced by the cow.

Butterfat: Protein Ratio

In a healthy cow butterfat levels should always be higher than milk protein. If this ratio is inverted, meaning the percentage of milk protein is greater than that of butterfat, the most common cause is rumen acidosis.

The next time you get your milk check, evaluate butterfat and protein levels to ensure your herd is performing optimally and receiving nutrients needed to meet production potential. Work with your nutritionist to maintain and boost component levels, ensuring rumen health is optimized to allow you to reap the greatest component benefits.

Source: Dr. Elliot Block, Senior Manager of Technology, Arm & Hammer Animal Nutrition. For more information, visit www.ahdairy.com.