  We present a high resolution study of the impact of realistic satellite
galaxies, extracted from cosmological simulations of Milky Way haloes including
6 Aquarius suites and Via Lactea \rom{2}, on the dynamics of the galactic disc.
The initial conditions for the multi-component Milky Way galaxy were generated
using the GalIC code, to ensure a system in dynamical equilibrium state prior
to addition of satellites. Candidate subhaloes that came closer than 25\,kpc to
the centre of the host DM haloes with initial mass enclosed within the tidal
radius, $M_\textrm{tid}$ $\ge$ 10$^{8} M_{\odot}$\,=\,0.003 $M_\textrm{disc}$,
were identified, inserted into our high resolution N-body simulations and
evolved for 2 Gyr. We quantified the vertical heating due to such impacts by
measuring the disc thickness and squared vertical velocity dispersion
$\sigma_{z}^{2}$ across the disc. According to our analysis the strength of
heating is strongly dependent on the high mass end of the subhalo distribution
from cosmological simulations. The mean increase of the vertical dispersion is
$\sim$ 20\,km$^{2}$\,s$^{-2}$\,Gyr$^{-1}$ for R $>$ 4\,kpc with a flat radial
profile while, excluding Aq-F2 results, the mean heating is $<$
12\,km$^{2}$\,s$^{-2}$\,Gyr$^{-1}$, corresponding to 28\% and 17\% of the
observed vertical heating rate in the solar neighbourhood. Taking into account
the statistical dispersion around the mean we miss the observed heating rate by
more than 3$\sigma$. We observed a general flaring of the disc height in the
case of all 7 simulations in the outer disc.
