  We study the entanglement spectrum of Heisenberg spin ladders of arbitrary
spin length S in the perturbative regime of strong rung coupling. For isotropic
spin coupling the the entanglement spectrum is, within first order perturbation
theory, always proportional to the energy spectrum of the single chain with a
proportionality factor being also independent of S. A more complicated
situation arises for anisotropic ladders of higher spin S>=1 since here even
the unperturbed ground state has a nontrivial entanglement spectrum. Finally we
discuss related issues in dimerized spin chains.
