Production and Quality in Dwarf Napier Grass Pasture Fertilized by Digested Effluent of Manure under Two-Years of Dairy Cow-Grazing in Warm Regions of Japan

Abstract

Dwarf Napier grass (Pennisetum purpureum) pasture is suitable for beef cow grazing in warm regions of Japan, while it is not assessed for the suitability by a herd of dairy cows in the region. This study was conducted to determine the effects of Digested Effluent (DE) application on herbage yield and quality, Herbage Consumption (HC) and Dry Matter Intake (DMI) under a paddock scale of rotational grazing by a herd of dairy cows on dwarf Napier grass pasture in southern Kyushu, Japan for two years in 2007 and 2008. Plant growth attributes, such as plant height, tiller number and herbage mass and HC increased consistently from the first to the second or third grazing cycle in the two years. Pre-grazing herbage mass was averaged at 176 and 193 g m^-2 in Chemical Fertilizer (CF) and DE treatments, respectively and HC and DMI did not differ between the two treatments. Overwintering ability was almost perfect in Miyazaki, judged by 97.1% of regrown plants in May 2008. Thus, dwarf Napier grass pasture fertilized with liquid DE can be utilized by dairy cow grazing as the same with CF fertilization, where DMI was averaged at 4.4 kg dry matter head^-1 day^-1 for 3 summer months in the two years.