  We report the first comparative study of strong MgII absorbers seen towards
radio-loud quasars of core-dominated (CDQs) and lobe-dominated (LDQs) types and
normal QSOs. The MgII associated absorption systems having a velocity offset v
< 5000km/s from the systemic velocity of the background quasar were also
excluded. Existing spectroscopic data for redshift-matched sightlines of 3975
CDQs and 1583 LDQs, covering a emission redshift range 0.39-4.87, were analysed
and 864 strong MgII absorbers were found, covering the redshift range
0.45-2.17. The conclusions reached using this well-defined large dataset of
strong MgII absorbers are: (i) The number density, dN/dz, towards CDQs shows a
small, marginally significant excess over the estimate available for QSOs; (ii)
In the redshift space, this difference is reflected in terms of a 1.6sigma
excess of dN/dz over the QSOs, within the narrow redshift interval 1.2-1.8;
(iii) The dN/dbeta distribution (with beta=v/c) for CDQs shows a significant
excess over the distribution found for a redshift and luminosity matched sample
of QSOs, at beta in the range 0.05-0.1. This leads us to infer that a
significant fraction of strong MgII absorption systems seen in this offset
velocity range are probably associated with the CDQs and might be accelerated
into the line of sight by their powerful jets and/or due to the accretion-disk
outflows close to our direction. Support to this scenario comes from a
consistency check in which we only consider the spectral range corresponding to
beta > 0.2. The computed redshift distribution for strong MgII absorbers
towards CDQs now shows excellent agreement with that known for QSOs, as indeed
is expected for purely intervening absorption systems. Thus, it appears that
for CDQs the associated strong MgII absorbers can be seen at much larger
velocities relative to the nucleus than the commonly adopted upper limit of
5000km/s.
