Relationship between in vitro digestibility and preference order of woodland plants by Hokkaido native horse

Abstract

Digestibility of diet could affect the preference of herbivore. In woodland, Hokkaido native horses graze selectively from some species of plants. In this experiment, the first experiment was conducted to evaluate the in vitro digestibility of 10 plants (Cacalia delphiniifolia, Cacalia hastata ssp.orientalis, Carex leucochlora, Cryptotaenia japonica, Pachysandra terminalis, Persicaria thunbergii, Petasites japonicus ssp. giganteus, Phryma leptostachya var. asiatica, Polygonum filiforme and Sasa nipponica) that Hokkaido native horses grazed in woodland. The second experiment was to determine a preference order of those plants by Hokkaido native horse. The in vitro digestibility was high in forbs (Cacalia hastata ssp.orientalis, Cryptotaenia japonica and Pachysandra terminalis) but low in gramineous plants (Carex leucochlora and Sasa nipponica). Contrary, horses preferred to eat gramineous plants rather than forbs. In this experiment, the woodland plants showed high in vitro digestibility did not correlate to the preference order by Hokkaido native horses.