TY - JOUR
T1 - Genetic evaluation of the longevity of the Holstein population in Japan using a Weibull proportional hazard model
AU - Sasaki, Osamu
AU - Aihara, Mitsuo
AU - Hagiya, Koichi
AU - Nishiura, Akiko
AU - Ishii, Kazuo
AU - Satoh, Masahiro
PY - 2012/2
Y1 - 2012/2
N2 - The objective of this study was to confirm the stability of the genetic estimation of longevity of the Holstein population in Japan. Data on the first 10 lactation periods were obtained from the Livestock Improvement Association of Japan. Longevity was defined as the number of days from first calving until culling or censoring. DATA1 and DATA2 included the survival records for the periods 1991-2003 and 1991-2005, respectively. The proportional hazard model included the effects of the region-parity-lactation stage-milk yield class, age at first calving, the herd-year-season, and sire. The heritabilities on an original scale of DATA1 and DATA2 were 0.119 and 0.123, respectively. The estimated transmitting abilities (ETAs) of young sires in DATA1 may have been underestimated, but coefficient δ, which indicated the bias of genetic trend between DATA1 and DATA2, was not significant. The regression coefficient of ETAs between DATA1 and DATA2 was very close to 1. The proportional hazard model could steadily estimate the ETA for longevity of the sires in Japan.
AB - The objective of this study was to confirm the stability of the genetic estimation of longevity of the Holstein population in Japan. Data on the first 10 lactation periods were obtained from the Livestock Improvement Association of Japan. Longevity was defined as the number of days from first calving until culling or censoring. DATA1 and DATA2 included the survival records for the periods 1991-2003 and 1991-2005, respectively. The proportional hazard model included the effects of the region-parity-lactation stage-milk yield class, age at first calving, the herd-year-season, and sire. The heritabilities on an original scale of DATA1 and DATA2 were 0.119 and 0.123, respectively. The estimated transmitting abilities (ETAs) of young sires in DATA1 may have been underestimated, but coefficient δ, which indicated the bias of genetic trend between DATA1 and DATA2, was not significant. The regression coefficient of ETAs between DATA1 and DATA2 was very close to 1. The proportional hazard model could steadily estimate the ETA for longevity of the sires in Japan.
KW - Dairy cow
KW - Genetic evaluation
KW - Survival analysis
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U2 - 10.1111/j.1740-0929.2011.00943.x
DO - 10.1111/j.1740-0929.2011.00943.x
M3 - Article
C2 - 22339689
AN - SCOPUS:84857191669
SN - 1344-3941
VL - 83
SP - 95
EP - 102
JO - Animal Science Journal
JF - Animal Science Journal
IS - 2
ER -