Lifetime Performance Index (LPI) Formula – April 2022

Where the relative emphasis placed on each of the three main components in each breed is presented in the following table along with the multiplicative factors for each component.

Breed

LPI Constant

Production

Durability

Health & Fertility

Emphasis

Factor Emphasis Factor Emphasis

Factor

Ayrshire

2004

46 .5685 32 .7215 22

.9561

Brown Swiss

959

55 .5440 27 .6786 18

.8349

Canadienne

932

55 .4565 30 .6653 15

.8759

Guernsey

644

50 .5540 35 .7523 15

.6923

Holstein

2200

40 .5408 40 .8243 20

.6967

Jersey

1087

50 .5970 30 .6387 20

.7483

Milking Shorthorn

1065

56 .5389 30 .7992 14

1.0363

Production Component (PROD):

PROD = [WPYx(PY-AvgPY)/SDPY] + [WPDxPD/SDPD] + [WFYx(FY-AvgFY)/SDFY] + [WFDxFD/SDFD]

Where PY = Protein Yield, PD = Protein Deviation, FY = Fat Yield and FD = Fat Deviation, which are standardized using the appropriate averages (Avg) and standard deviations (SD) and then multiplied by their respective relative weight (W), all of which are breed specific as outlined in the following table.

Parameter Trait Ayrshire Brown Swiss Canadienne Guernsey Holstein Jersey Milking Shorthorn
EBV Averages Milk Yield -372 -221 -256 -179 -328 -146 -195
Fat Yield -18 -7 -5 -8 -22 -13 -13
Protein Yield -14 -8 -4 -7 -15 -8 -6
EBV Standard Deviations Milk Yield 620 500 450 550 740 760 450
Fat Yield 25 20 11 23 28 34 19
Fat Deviation .21 .20 .20 .27 .28 .38 .16
Protein Yield 21 17 7 15 21 25 11
Protein Deviation .11 .12 .13 .10 .12 .16 .09
Relative Weights Within the Production Component Fat Yield 5.0 4.5 4.5 4.5 6.0 4.5 4.5
Fat Deviation 0.5 0.5 0.5 0.5 0.5
Protein Yield 5.0 4.5 4.5 4.5 4.0 4.5 4.5
Protein Deviation 0.5 0.5 0.5 0.5 0.5

Durability Component (DUR):

DUR = [WHL x (HL – 100)/5] + [WMS x MS/5] + [WF&L x F&L/5] + [WHH x (HH – 100)/5] + [WDS x DS/5] + [WRP x RP/5]

Where HL = Herd Life, MS = Mammary System, F&L = Feet and Legs, HH = Hoof Health, DS = Dairy Strength and RP = Rump, and each trait is standardized using the appropriate averages and standard deviations and then multiplied by their respective relative weight (W) that is breed specific as outlined in the following table.

Parameter Trait Ayrshire Brown Swiss Canadienne Guernsey Holstein Jersey Milking Shorthorn
Relative Weights Within the Durability Component Herd Life 4.0 4.0 2.0 3.4 2.0 2.0 2.6
Mammary System 3.8 3.2 5.5 3.2 3.7 4.0 4.0
Feet & Legs 2.2 1.6 2.5 2.4 2.1 4.0 2.6
Hoof Health 0.7
Dairy Strength 1.0 1.0 0.8
Rump 1.2 0.5

Health & Fertility Component (H&F):

H&F = [WDF x (DF-100)/5] + [WMR x (MR-100)/5] + [WSCS x (SCS-100)/5] + [WUD x UD/5] + [WMSP x (MSP-100)/5] + [WMT x (MT-100)/5]

Where DF = Daughter Fertility, MR = Mastitis Resistance, SCS = Somatic Cell Score, UD = Udder Depth, MSP = Milking Speed and MT = Milking Temperament.  The relative weights for each trait (i.e.: WDF, WMR, WSCS, WUD, WMSP and WMT, respectively), which are specific to each breed, are provided in the following table.

Parameter

Trait

Ayrshire

Brown Swiss Canadienne Guernsey Holstein Jersey

Milking Shorthorn

Relative Weights Within the Health & Fertility Component Daughter Fertility

4.0

4.0 4.0 6.7 6.7 5.0

2.0

Mastitis Resistance

1.0

3.3

5.0

Somatic Cell Score

3.0 3.0 2.0

4.8

Udder Depth

1.0

2.0 1.0

2.4

Milking Speed

3.0

2.0 1.0 0.3

0.8

Milking Temperament

2.0

Share

Share on facebook
Share on twitter
Share on email
By Brian Van Doormaal
Brian has dedicated his professional career of nearly 35 years involved in the genetic improvement of dairy cattle in Canada. He is well-known for his numerous extension articles and public speaking engagements in both official languages.