  In this study, we use a single-mode squeezed thermal vacuum state formalism
and examine the nature of a massive homogeneous scalar field, minimally coupled
to the gravity in the framework of semiclassical gravity in the Bianchi type-I
universe. We have obtained an estimate leading solution to the semiclassical
Einstein equation for the Bianchi type-I universe shows, each scale factor in
its respective direction obeys t^(2/3) power-law expansion. The mechanism of
the nonclassical thermal cosmological particle production is also analyzed in
the Bianchi type-I universe.
