  We are concerned with the formation of singularity and breakdown of strong
solutions to the Cauchy problem of the three-dimensional full compressible
magnetohydrodynamic equations with zero heat conduction. It is proved that for
the initial density allowing vacuum, the strong solution exists globally if the
deformation tensor $\mathfrak{D}(\mathbf{u})$ and the pressure $P$ satisfy
$\|\mathfrak{D}(\mathbf{u})\|_{L^{1}(0,T;L^\infty)}+\|P\|_{L^{\infty}(0,T;L^\infty)}<\infty$.
In particular, the criterion is independent of the magnetic field. The
logarithm-type estimate for the Lam{\'e} system and some delicate energy
estimates play a crucial role in the proof.
