Detailed Dairy Cattle Evaluation Information
2017/05/24
Index to rank animals
Three different indices, EBV (yen), NTP (Nippon Total Profit index) and Lifetime Merit(yen) are published in Japan. In addition, cow EPA (yen) is calculated using same formula to EBV (yen) but replacing EBV to EPA (Estimated Production Ability = EBV + PE). NTP is more popular in Japan now.

EBV (yen) are calculated from evaluations of production traits based on the milk pricing system in Japan:
EBV(yen) = EBV(Mkg) * a

+ 4 * (EBV(Mkg) * (EBV(F%) + Fbase/Mbase * 100- 3.5) + Mbase * EBV(F%))

+ 4 * (EBV(Mkg) * (EBV(S%) + Sbase/Mbase * 100- 8.3) + Mbase * EBV(S%))
where,
a:
fluid milk price in yen, updated every year,
Mkg:
Milk(kg),
F%, S%:
Fat(%) and SNF(%),
Mbase, Fbase, Sbase:
the average milk, fat and SNF yields (kg) of the cows born in genetic base year.
 
Milk was priced by SNF but not by protein in Japan, and that is the reason why SNF are still recorded in DHIP and evaluated in Japan.


Lifetime Merit(yen) was introduced by HCAJ(2011). Lifetime Merit enphasize production life and fertility rather than NTP. Lifetime Merit is calculated by the following formula:
Compornent trait weight
Production(40) FAT(kg) 11
SNF(kg) 23
FAT(%) 6
Durability(40) Herd Life 26
Overall feet and legs 4
Udder Component 8
Rump angle 2
Health and fertility(20) Body condition score 14
Somatic cell score -6
 
NTP was introduced by HCAJ (LIAJ, 1996; Suzuki et al., 1996) and used to rank animals based on the longevity performance of cows. NTP is calculated by the following formula in 2015( rerision in the year 2010 was passed):

NTP = 7.0 * PC + 1.8 * DC + 1.2 * HFC

PC (Production Component) = 38 * (Fkg / SD(Fat)) + 62 * (Pkg / SD(Prt))

DC (Durability Component) = 35 * (EBV(FL) / SD(FL)) + 65 * (UC / SD(UC))

UC (Udder Component) = 0.17 * EBV(U) + 0.83 * ( 0.18 * EBV(FU) + 0.09 * EBV(RUH) + 0.10 * EBV(US) + 0.24 * EBV(UD) + 0.07 * EBV(FTP) - 0.10 * EBV(TL) - 0.22 * EBV(RTP))

HFC (Health and Fertility Component) = (-33 * ( EBV(SCS) - (Average of EBV(SCS) of cows were born in base year)) / SD(SCS) + 17 *( EBV(PER) / SD(PER) - 50 * ( EBV(DO) - Average of EBV(DO)) / SD(DO))

where,

PC:
Production Component,
DC:
Durability Component,
HFC:
Health and Fertility Component
Mkg, Fkg, Pkg:
Milk, Fat and Protein yields in kg,
SD(Fat), SD(Prt), SD(FL), SD(UC), SD(SCS):
standard deviation of fat, protein, over all feet and legs, udder component and somatic cell score
FL:
overall Feet and Legs,
U:
overall Udder,
FU:
Fore Udder,
RUH:
Rear Udder Height,
US:
Udder Support,
UD:
Udder Depth,
FTP:
Front Teat Placement,
TL:
Teat Length,
RTP:
Rear Teat Placement.
PER:
Persistency,
DO:
Days Open,