  In this work we discuss the non-collinear ground-state reported for GdGa on
the basis of a model Hamiltonian considering anisotropic exchange interactions.
We show that a competition between intra and inter-sublattice exchange
interactions can lead to a canted structure, which competes with a collinear
(ferro or antiferromagnetic) order. The mean-field thermodynamic analysis of
the model for $S=7/2$ shows a good agreement between calculated and reported
experimental data of the canting angle and isothermal entropy change for GdGa.
