Effects of herbage mass, nutritive value of herbage, amount of supplement intake, milk yield and species of grass in the pasture on herbage intake of grazing dairy cows

摘要

The objective of this study was to determine the factors that affect herbage intake of dairy cows grazed on intensively managed pasture. Two cows per ha were grazed all day, and about half of the total digestible nutrients (TDN) demand of cows was supplied by supplements. Means of herbage mass (dry matter g/m~2, 4 cm in cutting height) and content of TDN (percent) were 164.1 +- 66.3 and 70.9 +- 4.2 in the daytime pasture and 99.2+- 25.7 and 68.1 +- 4.5 in the nighttime pasture, respectively. Mean daily milk yield and herbage intake of cows were 31 kg, head and 1.75 kg/100 kg of body weight, respectively. Herbage intake was most greatly affected by herbage mass and decreased as intake of supplement increased. The grass species in the pasture had only a slight effect on herbage intake, and the TDN content of herbage had almost no effect on herbage intake. A positive correlation was seen between herbage mass and TDN intake from grazing for cows that were grazed in a daytime pasture in which the herbage mass per 100 kg of body weight was less than 8 dry matter kg.