  The angular momentum vector of a Heisenberg ferromagnet with isotropic
exchange interaction is conserved, while under uniaxial crystalline anisotropy
the projection of the total spin along the easy axis is a constant of motion.
Using Noether's theorem, we prove that these conservation laws persist in the
presence of dipole-dipole interactions. However, spin and orbital angular
momentum are not conserved separately. We also define the linear momentum of
ferromagnetic textures. We illustrate the general principles with special
reference to the spin transfer torques and identify the emergence of a
non-adiabatic effective field acting on domain walls in ferromagnetic
insulators.
