Making sense of milk fatty acid results

Posted on March 30, 2022 in Dairy Performance
Making sense of milk fatty acid resultsBy Stacy Nichols
Has your processor offered your farm milk fatty acid analysis?  Milk fatty acids can be economically analyzed with mid-infrared technology, and many processors are beginning to offer this service to farms.  Here’s an overview of milk fatty acids to help you interpret the results.

Categorizing milk fatty acids
Milk fatty acids are divided into three categories:

  • De novo fatty acids (C 4:0 to C 15:0) are produced by the mammary gland from the volatile fatty acids acetate and butyrate (which are produced in the rumen).
  • Preformed fatty acids (C 18:0 and greater) originate from dietary fatty acids (naturally in feedstuffs and rumen-inert fat supplements) and body fat mobilization.
  • Mixed fatty acids:  Because C 16:0 can originate as a de novo or a preformed fatty acid, we refer to C 16:0 and C 16:1 as mixed fatty acids.

The value of de novo fatty acids
In Holstein data from Cornell University, Miner Institute, St. Albans Creamery, and Delta Instruments, de novo milk fatty acid percentage is positively correlated with milk fat percentage and milk protein percentage.  Herds with high de novo production had higher milk fat (+0.20 percentage points) and higher milk protein (+ 0.11 percentage points).  Preformed milk fatty acids were not correlated with milk fat percentage.

Influencing your herd’s milk fatty acid results
Two main metrics can be evaluated to achieve milk fat greater than 3.75%:

  1. De novo milk fatty acids should be greater than 0.85%.
  2. De novo milk fatty acids plus mixed fatty acids should be greater than 2.25%.

Milk fatty acids are often herd-dependent, influenced by feed ingredients, stage of lactation, cow comfort and/or other management factors.  Feeding vegetable oil that is readily available in the rumen (e.g., full-fat distillers grains, hominy feed, whole soybeans) often decreases de novo milk fatty acids, causing milk fat depression.  Conversely, feeding vegetable oil in a more protected form (e.g., whole cottonseed) or supplemental fat products can often increase de novo milk fatty acids and milk fat percentage.  Bodyweight loss by cows in early lactation increases preformed milk fatty acids.

Contact your Vita Plus consultant to discuss your farm’s milk fatty acid results and strategies to potentially increase your herd’s milk components.

About the author:  Stacy Nichols is a Vita Plus dairy technical specialist.  He grew up in northwest Illinois and finished high school in northeast Georgia.  He received his bachelor’s and master’s degrees in dairy science from the University of Georgia.  Nichols was the herdsman at Mississippi State University’s Bearden Dairy Research Center from 1994 to 1996.  He then returned to Georgia as the herdsman on a private 350-cow dairy.  Since 1997, he has been involved in the dairy feed industry on a local, national and global level.  Nichols has considerable experience in transition cow management, nutritional modeling and amino acid formulation. He and his wife, Melissa, have eight children and reside in northwest Indiana.

Category: Dairy Performance
Feed additives
Feed quality and nutrition
Milk production and components