Select Sires

Choose Merit Value to Fit Milk Market

Net Merit Dollars (NM$), Fluid Merit Dollars (FM$) and Cheese Merit Dollars (CM$) are three selection indexes the U.S. Department of Agriculture provides to fit the different ways in which dairy producers are paid for milk. These values have been provided in the past, but with the new revisions to milk-component values in the merit formulas, these selection indexes have become more useful.

The biggest changes are in the FM$ formula. The previous versions of this index included a negative weight on Predicted Transmitting Ability for protein. While milk sold for fluid consumption usually doesn’t earn a premium for protein, reducing protein content in the milk is not a wise long-term strategy, either. The new formula has removed the negative weight for PTA protein and now is much more useful for producers who receive little or no payment for the protein in their milk. The following table shows the differences between the old and new Fluid Merit formulas.

Table 1. Comparison of weights assigned to various components of the formula to calculate Fluid Merit Dollars, May 2003 and August 2003.

Trait	Previous FM$ All Breeds	New FM$ Holsteins
Milk	43%	24%
Fat	16%	22%
Protein	-12%	9%
Productive Life	11%	11%
Somatic Cell Score	-7%	-9%
Udder Composite	5%	7%
Feet-and-Leg Composite	3%	4%
Body-Size Composite	-3%	-3%
Daughter Preg. Rate	0%	7%
Service-Sire Calv. Ease	0%	-2%
Daughter Calving Ease	0%	-2%

The new formula for NM$ includes no value for PTA milk. Because of this, it is not the best choice for producers who sell to fluid-milk markets. The NM$ formula is designed for those producers in multiple-component pricing markets who receive a moderate payment for protein.

The new CM$ formula is similar to the previous one except for the addition of DPR and calving ease. It includes a negative weight on PTA milk and emphasizes higher percents for milk components. It also includes a strong emphasis on protein, so CM$ is a choice for producers who supply milk to cheese plants and receive a premium for the protein in their milk.

According to USDA recommendations, if producers receive less than $1.65 per pound of protein, then using FM$ would be the best option. Producers who receive more than $2.65 per pound of protein are advised to use CM$. PTAs for NM$ are designed for producers who receive somewhere between $1.65 and $2.65 per pound of protein.

Of course, conditions and individual preferences can vary widely. Some producers may want a simpler approach or may feel the traits need to be combined differently. With the use of a spreadsheet, calculating a customized index using current sire evaluations can be done rather easily. It’s just a matter of choosing the traits you want included, dividing them by their standard deviation (see Table 2), applying the desired weighting factor and then summing up the traits. For example, the calculation for an index that is two parts PTA milk, one part udder composite (UDC) and one part feet-and-leg composite (FLC). would be: 2 * (PTA milk/832) + (UDC/0.78) + (FLC/0.88).

Table 2. Standard deviations for traits used to calculate PTAs for NM$.

Trait	Standard Deviation
Milk	832
Fat	32
Protein	25
Productive Life	1.5
SCS (subtract 3.1)	0.20
Udder Composite	0.78
Feet-and-Leg Composite	0.88
Body-Size Composite	0.94
Daughter Pregnancy Rate	1.4
Service-Sire Calv. Ease (subtract 8)	1.7
Daughter Calving Ease (subtract 8)	1.4

USDA provides more options than NM$ for sorting A.I. sires. The option that fits best for each dairy producer depends on the milk prices he receives. FM$ has not received much attention in the past, but with the recent changes it deserves a second look. If the three options provided by USDA don’t meet an individual producer’s needs, then calculating a customized index may be an option. There is a large amount of available sire-evaluation information, and selection indexes can be useful tools to help sort through the data.

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Select Sires Inc., 11740 U.S. 42 North, Plain City, Ohio 43064 / Phone: (614) 873-4683 Fax: (614) 873-5751