TABLE 2.

Estimates of additive genetic variance (${\widehat{\mathrm{\sigma }}}_{\text{a}}^2$), residual variance (${\widehat{\mathrm{\sigma }}}_{\text{e}}^2)$, and heritability (${\widehat{\text{h}}}^2)$ for eight longevity traits in Chinese Holsteins.

Trait1	N	${\widehat{\mathrm{\sigma }}}_{\mathbf{a}}^{\mathbf{2}}$	${\widehat{\mathrm{\sigma }}}_{\mathbf{e}}^{\mathbf{2}}$	${\widehat{\mathbf{\text{h}}}}^{\mathbf{2}}$
Lon11	103,479	725.13 ± 64.05	7,333.92 ± 58.52	0.090 ± 0.008
Lon12	90,279	2,812.37 ± 292.38	42,117.79 ± 301.72	0.063 ± 0.006
Lon13	82,826	5,557.25 ± 610.59	98,433.22 ± 680.48	0.053 ± 0.006
Lon14	79,571	8,111.88 ± 903.21	151,005.01 ± 1,038.21	0.051 ± 0.006
Lon15	78,144	10,476.65 ± 1157.65	186,076.45 ± 1,309.04	0.053 ± 0.006
ML	78,227	7,811.06 ± 995.05	187,066.34 ± 1,237.10	0.040 ± 0.005
PL	78,227	9,627.98 ± 1,236.02	241,743.18 ± 1,574.84	0.038 ± 0.005
HL	78,227	9,602.13 ± 1,232.00	241,404.44 ± 1,571.52	0.038 ± 0.005

¹Lon11, the days from the first calving to the end of the first lactation or culling; Lon12, the days from the first calving to the end of the second lactation or culling; Lon13, the days from the first calving to the end of the third lactation or culling; Lon14, the days from the first calving to the end of the fourth lactation or culling; Lon15, the days from the first calving to the end of the fifth lactation or culling; PL, productive life referring the days from the first calving to culling or death; ML, milking life referring the days from the first calving to culling or death but excluding all dry periods; HL, herd life referring the days from birth to culling or death.