Mature Equivalent Items

Dairy Comp uses several items for calculating mature equivalent. Two of the items are ME305 and 305ME. These items are similar in that both express predicted performance "adjusted" for age, and stage of lactation. ME305 is the item internally calculated by Dairy Comp while 305ME is calculated externally, usually by the processing center for herds using a DHI system. Dairy Comp, along with each processing center, calculates ME305s slightly differently. For this reason, it is more useful to pick one item and monitor it consistently rather than compare the items among each other.

Calculating ME

In order to calculate the Mature Equivalent, Dairy Comp needs to know a Fresh Date (FDAT), and Birth Date (BDAT) for the animal. If animals are missing ME's, it is likely due to missing birth dates. Check the birth date item first (BDAT) and if it is empty, estimate a birth date.



The ME Factor itself is stored in item number 55, called MEFAC (it may occasionally be named PCAR in older cow files). You can LIST or SHOW it for verification. The MEFAC is added to the straight 305 projection for heifers and geriatric cows in order to level the playing field. It is recalculated and stored during the FRESH event. For new cows it is put in with the LOAD. If this item is a zero, the ME305 (Dairy Comp internally calculated ME, not DHI) and internal RELV item will be zero.

The CONVERT command has an option to (re) calculate ME factors for the entire herd. This is a "safe" procedure and can be run any time, and is recommended if all cows missing ME Factors. Occasionally, animals added with ADD or FILEIN will be missing ME Factors. If this is the case, they probably need their birth dates entered (or estimated). If there are still cows with missing ME Factors, and you used CONVERT to reset all factors, check that you are not using the item MEFAC (or PCAR, item 55) for your own purposes and wiping out the ME factors .

Note that the fresh table item manipulations come BEFORE the ME Factors storage and therefore will not hurt anything by zeroing or transferring PCAR or MEFAC. However, it is taking up space in the fresh table which you may need for something else.



Each time you run RECEIVE Dairy Comp takes whatever the processing center reports as the "305ME" and puts it onto page 4 of the cow cards. Dairy Comp does not know whether it is a ME or not., but in most DHI interfaces it is an ME. The exception is Wisconsin (AgSource). The page 4 ME305s are type 86 items and usually called 305ME.

Dairy Comp can also calculate both a "straight" 305 and a mature equivalent 305. You can make items for these in the 120 series. In some cases, a 305 is not available (such as in "Generic" RECEIVE or lab file loads). If the 305ME is not available, Dairy Comp will put it's own 305ME onto the test day (Page 4) records.

In daily milk enabled herds Dairy Comp's ME305's are actually more accurate since the weekly average curves are not estimated.

The other source of variation in the 305's is due to DHI adjustments for CAR coded cows. Dairy Comp does not use these CAR code adjustments. They are a difficult to program and vary between processing centers.

Most users use ME's only, especially the diehards who like to compare changes in 305ME in order to evaluate management changes such as BST (for example the change in the current 305ME to the previous 305ME).

There is an OP on item 86 that can either "ME" a 305, or "UnME" a 305. This way, users with straight 305's can still compare ME's.


Relative Value (RV)

Dairy Comp has two items called Relative Value - RV and RELV. Relative value is the mature equivalent 305 expressed as a percentage of the herd average ME. It is calculated monthly by RECEIVE. RV is based on ME305, which is internally calculated while RELV is based on 305ME, usually externally calculated. Since 100 is an average relative value for the herd, cows with higher RVs are typically cows with higher MEs and cows below 100 are those with lower ME values.


List of Item Types

Item names are only that- names. It is the item type that is important. Below is a list of the 305 projected items, including item types:


Common Name Type Op1 Op2


305ME    86 -1 0 

Latest 305ME as received from the processing center. This is usually an ME with the exception of Wisconsin and some private testing organizations.


ME305   120 0 0 

Dairy Comp internal projected mature equivalent (ME) 305.

M305   127 0 0 

Dairy Comp internal projected 305, not ME.


Add Op2 to the type 86 items to get ME or undo ME


305x   86 -1 1 

Latest 305 multiplied by the ME factor to make it an ME. In Wisconsin, use this to get MEs for any test just by changing the Op1.


305y   86 -1 2 

Latest 305 divided by the ME factor to "undo" the ME and return a "straight" 305.


Change the Op1 to get different tests. Negative Op1s give previous test day information:

   86 -1 0 latest test

   86 -2 0 first previous test

   86 -3 0 second previous test


Positive Op1s go forwards beginning with the first test.

   86 1 0 first test

   86 2 0 second test

   86 3 0 third test