Fractal analysis for quantification of grazing paths of cows on homogeneous pastures

Fractal analysis was applied to grazing paths in non-patchy environments to clarify the behavioral information available from the analysis and to evaluate the effect of social factors on grazing paths. The grazing paths of Holstein Friesian cows in groups of 4 (GROUP-4) and 10 cows (GROUP-10) on a spatially homogeneous pasture were observed. Application of fractal analysis could quantify three aspects of grazing paths of cows: (1) hierarchical scales, (2) structure and (3) sinuosity by scale. In this study, regardless of the group size, the hierarchical scale of grazing paths was approximately 10 m. The paths showed different patterns below and above the 10 m scale. For both group sizes, fractal dimension (an index of sinuosity) below the 10 m scale was smaller than fractal dimension above 10 m scale suggesting that the paths below the 10 m scale were straighter than that above the 10 m scale. The fractal dimensions below and above the 10 m scale were significantly larger for GROUP-4 than for GROUP-10 (P < 0.05). Sinuosity of paths of GROUP-4 was higher than that of GROUP-10 over the entire scale. From these three aspects, fractal analysis can clarify the factors related to grazing paths of herbivores.

► Grazing paths of cows on homogeneous pastures were quantified by fractal analysis.
► The grazing paths of cows showed hierarchical scale of 10 m.
► The path sinuosity below the 10 m scale was smaller than that above the 10 m scale.
► Small group size increased the sinuosity of grazing paths of cows over the scale.
► Fractal analysis allows us to investigate grazing paths on non-patchy environments.