  Self-consistent solutions to the nonlinear spinor field equations in General
Relativity has been studied for the case of Bianchi type-I (B-I) space-time. It
has been shown that, for some special type of nonliearity the model provides
regular solution, but this singularity-free solutions are attained at the cost
of broken dominant energy condition in Hawking-Penrose theorem. It has also
been shown that the introduction of $\Lambda$-term in the Lagrangian generates
oscillations of the B-I model, which is not the case in absence of $\Lambda$
term. Moreover, for the linear spinor field, the $\Lambda$ term provides
oscillatory solutions, those are regular everywhere, without violating dominant
energy condition.
  Key words: Nonlinear spinor field (NLSF), Bianch type -I model (B-I),
$\Lambda$ term
  PACS 98.80.C Cosmology
