Table 2.

The genetic architecture of milk production traits and Fertility estimated by ASReml

	Additive genetic variance (${\sigma }_g^2$)	Additive polygenic variance (${\sigma }_a^2$)	Error variance (${\mathrm{\sigma }}_e^2$)	Heritability (h 2)
FatY	118.594	48.689	234.326	0.421
MilkY	114.827e + 03	38.532e + 03	135.598e + 03	0.528
ProtY	72.488	36.072	140.417	0.443
Fat%	0.056	0.008	0.018	0.781
Protein%	0.012	0.003	0.003	0.818
Fertility	42.990	0.003e-01	340.287e-01	0.013
FatY_HTa	0.041	0.581e-07	0.571	0.072
MilkY_HTa	0.004	0.353e-06	0.035	0.091
ProtY_HTa	0.035	0.564e-07	0.561	0.059

^aLabels the traits of Fat yield, milk yield, and protein yield under heat stress