PROGRESSIVE PERFORMANCE RANKING (2007)

The Brown Swiss Progressive Performance Ranking (PPR) is the ranking system for sire and cow genetic evaluations. 
The formula has weights which add to 100 and, thus, are comparable to the percentage weight for each variable. 

The PPR Formula

D2020    [30(PTA_protein/SD_protein) + 22(PTA_fat/SD_fat) + 8(PTA_PL/SD_PL) + 10(PTA_UDC/SD_UDC)

                  + 6(PTA_MO/SD_MO) + 16(PTA_DPR/SD_DPR) + 4(PTA_LIV/SD_LIV) - 4(PTA_SCS-3.06/SD_SCS) ]

D2017    [34(PTA_protein/SD_protein) + 28(PTA_fat/SD_fat) + 6(PTA_PL/SD_PL) + 10(PTA_UDC/SD_UDC)

+ 6(PTA_MO/SD_MO) + 12(PTA_DPR/SD_DPR) + 4(PTA_LIV/SD_LIV) ]

where:    
PL = Productive Life
UDC = Udder Composite (See Formula below)
MO = Mobility
DPR = Daughter Pregnancy Rating
LIV = Livability
SD = Standard Deviation of corresponding traits follow:

Trait                             Standard Deviation
Protein                                    15.90
Fat                                           22.10
PL                                             2.10
UDC                                          0.65
MO                                            0.68
DPR                                           1.40
LIV                                             1.40 
SCS                                            0.12

Since the weights sum to 100, the divisor is (100/100) or 1.

Udder Composite

UDC Formula:

(UDC) = .22(PTA_FUA/SD_FUA) + .18(PTA_RUH/SD_RUH) + .22(PTA_RUW/SD_RUW) +

.18(PTA_UC/SD_UC) + .10(PTA_UD/SD_UD) + .10(PTA_TP/SD_TP) 

    
  Corresponding Standard Deviations