  We derive an expression for the entropy of a dark matter halo described by a
Navarro-Frenk-White model with a core. The comparison of this entropy with the
one of dark matter at the freeze-out era allows us to constraint the parameter
space in mSUGRA models. Moreover, joining these constraints with the ones
obtained from the usual abundance criteria and demanding both criteria to be
consistent with the 2$\sigma$ bounds for the abundance of dark matter:
$0.112\leq\Omega_{DM}h^2\leq0.122$, we are able to clearly discriminate
validity regions among the values of $\tan \beta$, one of the parameters of the
mSUGRA model. We found that for the explored regions of the parameter space,
small values of tan$\beta$ are not favored; only for tan$\beta\simeq50$ are
both criteria significantly consistent. In the region where both criteria are
consistent we also found a lower bound for the neutralino mass, $m_{\chi}\geq
141$ GeV.
