Optically excited uniform magnetization precession in the ferromagnetic state of La0.67Ca0.33MnO3 films grown on different substrates is investigated by the time-resolved magneto-optic Kerr effect. The parameters of magnetic anisotropy are determined from the measured field dependence of the precession frequency. The dominant anisotropy contribution in the film grown on SrTiO3(001) is the strain-induced easy-plane anisotropy. In the strain-free films on NdGaO3(110), we discover a uniaxial in-plane anisotropy that results from the interface due to the tilting of the oxygen octahedra in NdGaO3.