Many factors can impact a cow’s productivity, and there are just as many tips and tricks to help address production challenges on a dairy farm. Along with herd management, feed additives are valuable tools to support and achieve milk yield and component goals.

Tucker hannah
Ruminant Technical Manager / Novus International Inc.

By working with the farm’s nutritionist, owner and herd manager to identify the source of changes in milk or component production, our team can develop customized feeding strategies to optimize milk and component yields.

On-farm trial

In a recent project with a 3,000-head dairy farm in the southwest U.S., we worked with a nutritionist who noticed the cows were struggling to meet production goals. The nutritionist on the farm believed this was due to low de novo milk fatty acid production.

Milkfat is composed of different fatty acid types, with the main two being de novo and preformed fatty acid. De novo fatty acids are synthesized in the mammary gland, while preformed fatty acids come from feedstuffs in the diet or adipose tissue. For de novo fatty acids, the rumen must synthesize volatile fatty acids (VFAs) that are first transported to the mammary gland before becoming part of the milkfat. De novo and preformed fatty acids are ultimately combined in the mammary gland to produce milkfat (Figure 1).

Industry research shows a positive relationship between higher concentrations of de novo fatty acids and increases in milkfat levels. For this reason, our team believed a methionine supplement could aid in the production of milkfat on the farm.


This feed supplement has been shown to support fiber-digesting bacteria in the rumen responsible for decreasing the negative impact of trans-10, cis-12 conjugated linoleic acid (CLA), a strong inhibitor of milkfat production. By adding the feed supplement to the diet, thereby limiting the impact of CLA, preformed fatty acid synthesis is promoted and de novo fatty acid synthesis is maintained, ultimately improving the milkfat concentration of the milk.

The nutritionist at the farm was aware of the supplement through peer-reviewed literature and recent work by Dr. Kevin Harvatine’s team at Penn State University and agreed with the team’s suggestion to add the feed supplement to the herd’s diet.

45-day challenge results

At the farm, the feed supplement was added at 0.1% of dry matter intake (DMI). Within week three of the 45-day trial period, milkfat content had increased by 0.2%. Analysis on the farm also showed specific improvements in de novo fatty acids and mixed-origin fatty acids, demonstrating the physiological benefits of adding the feed supplement to the ration.

The nutritionist shared that the feed supplement significantly improved the dairy’s income over feed cost (IOFC), generating additional revenue for the farm. They said any tool in a nutritionist’s toolbox that can consistently improve IOFC across multiple dairy operations is incredibly valuable. Thanks to the positive results, the farm chose to continue using the supplement after the 45-day trial was complete.

Return on investment is very important with any feed additive, especially in times when raw feed costs and other inputs are high. For this reason, nutritionists and producers do their homework – scrutinizing the cost of every decision to identify the positive returns – so they can find the best tool to address their challenges. 

Talk with your nutritionist or industry representative to learn how a methionine supplement can support the goals of your herd.