[en] The correlations function magnetization fluctuations in Heisenberg ferromagnets Eu O and Eu S has been obtained from mode-coupling theory. In the critical region the simplified integral equation can be used but the dipolar interaction must be taken into account in order to explain the puzzling results of spin-echo experiments. For intermediate and high wave-vectors the microscopic features of the magnetic interaction turn out to be essential. The numerical solution of the mode-coupling equation has been obtained for the three cubic lattices allowing for interactions beyond nearest neighbours. The results for fcc ferromagnetic europium compounds are in good agreement with recent high resolution neutron scattering data. Similar good agreement is found with very recent experiments in Pd₂ Mn Sn. For a bcc lattice the equations have been solved adopting various sets of exchange constants proposed to interpret the magnetic properties of iron. The importance of the proper lattice structure and interactions is shown. (author)