A cattle grid comprising a first group of fixed bars (12) that are spaced apart with gaps therebetween and a second group of bars (20) that are movable between a lower position and an upper position. With the bars of the cattle grid in a first configuration, the second group of bars (20) are in the lower position, such that the upper portions of the bars of the second group (20) are lower than the upper portions of the bars of the first group (12), whereby gaps are defined between the bars of the first group to provide a barrier to the passage of animals. When the set of bars are in a second configuration, the second group of bars (20) are in the upper position such that the second group of bars (20) intermeshes with the first group of bars (12) so that the bars of the second group (20) occupy the gaps between the bars of the first group (12) to allow passage of animals across the bars.