Experimental observations on the heavy hadron production has shown baryon over meson ratios that were unexpected both in $AA$ and $pp$ collisions. In $AA$ collision
the $\Lambda_c/D^0$ ratio has a value close to one, and in $pp$ collision the ratio between charm baryons $\Lambda_c$, $\Xi_c^0$ and $\Omega_c^0$ respect to $D^0$ meson is larger than the one measured in $e^+e^-$, $ep$ collisions. The assumption of the simple fragmentation as hadronization process in these collisions is not sufficient to describe these evidences.
We will show a brief recap of some theoretical efforts that has been made to catch the features of this collision stage.