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CSI-Dairy: Variations in production


Dr. Jeff Mikus is a a Dairy Technical Service Specialist in the Western United States for Diamond V. Contact him via e-mail jmikus@diamondv.com; phone 806-438-6836 or visit www.diamondv.com.Numerous ‘culprits’ exist on dairy farms, robbing herd performance and injuring the dairy’s bottom line. Identifying and arresting the offender isn’t always easy, and often requires a full investigation, gathering and analyzing evidence on the farm and in the lab. This month’s investigator found variations among feeders produced unwanted results.     


By Jeff Mikus, Ph.D. 


The manager at the large western dairy was puzzled. You could hear it his voice. Uneven production levels were causing concerns. The dairy suspected feeding procedures, but no one could identify just what.

A TMR Audit™ was conducted. Many observations made throughout the auditing process typically paint a picture of opportunities on the dairy. This dairy had two feeders feeding about 4,000 cows, but we discovered they were doing their jobs quite differently. Feed delivery and consistency of diet particle distribution exposed the differences.


Picture 1. Nice, even delivery from Feeder A

Feed delivery

Both feeders used the same brand of equipment in similar 

working conditions. However, the pictures show differences in deliveries between the two feeders. Feeder A (Picture 1) delivered feed, as we would expect, tight to the stem wall and very evenly distributed to all headlocks along the bunk.

Feeder B (Pictures 2 and 3) encountered real challenges in feed delivery. The feed was very wavy, and not all headlocks in the pen had the same amount feed. 

In this case, the pen was a fresh pen filled to 100% capacity. Yet, 15% of the headlocks had no access to feed. Delivering feed to a full pen in this manner can have very detrimental consequences.


Picture 2. Feed not delivered to all headlocks in a fresh pen by Feeder B

Feed consistency

The feeders also produced diets with varying levels of  consistency. We use particle size distribution is used to determine the consistency of diets between loads and mixers. Consistency of the feed is measured by collecting 10 samples per diet over the length of the delivery, shaking them through a Penn State Shaker Box, and calculating a coefficient of variation (CV) between samples for each screen. CV is a statistical measure of variation. The lower the CV, the lower the variability between the group of numbers in question. Based on more than 1,000 observations, the top 25% of feeders can achieve a coefficient of variation below 3% in the middle and bottom screens. 

Tables 1 and 2 show the consistency of high cow diets mixed by the feeders. Although Feeder B had an acceptable coefficient of variation (less than 5%), Feeder A wasexecuting his job much more consistently.

Picture 3. Wavy feed-out and headlocks without feed in same fresh pen



After conducting the TMR Audit, observations were shared with the feeders and managers. Changes were made, and consistency in diets and production followed. Within the month, the producer attributed an increase in milk production and herd health to a more consistent diet. 

Each dairies goal should be to deliver the most consistent diet possible to every cow, every day. Achieving this goal requires a focus on managing ingredients, equipment, and educating feeders on proper techniques. This training should include every employee who ever helps feed. Consistency among feeding personnel helps reduce variation associated with feeding systems, yielding consistent rumen function and production.


These tables show the consistency of high cow diets mixed by the feeders. Although Feeder B had an acceptable coefficient of variation (less than 5%), Feeder A was executing his job much more consistently.

Each month, DairyBusiness Communications will check the case files of lead dairy ‘investigators’ to uncover another ‘CSI-Dairy’ mystery. Episodes are archived at www.dairybusiness.com.