Abstract: Cast grates, especially for pig stables, have parallel bars with two slits between them and connecting end bars at their ends. Between these end bars are bridges displaced from bar to bar along a bridge curve, such as a sine wave or sawtooth wave. Tread surfaces on each bar have convex shoulders contiguous with concave flank surfaces at inflection points. All tangential planes of the flanks have a clear distance from the neighboring bar. The tread and bridge surfaces have a slope toward the slit between 1/2 and 1/16, and preferably about 1/8.