Effect of Grazing Stage and Intensity on the Forage Production and Nutritive Value in Orchargrass Dominant Pasture

Orchargrass 위주 혼파초지에서 방목시기와 강도가 초지생산성 및 사료가치에 미치는 영향

A field experiment was carried out to determine the effects of grazing stage and intensity on the forage production and nutritive value in orchardgrass dominant pasture, 1989 and 1990. The grazing stages were 20- 25m, 30-35cm and 40-45cm of plant height, and high and medium grazing intensity were set by the number of growing cows (initial body weight: 230-250kg), which was adJusted according to the pasture production. The high level of grazing intensity was 150% of medium intensity. Annual grazing frequency was 10 times in 20-25cm. 8 times in 30-35cm. and 6 times in 40-45cm of plant height. Dry matter(DM) yield was increased with increasing of plant height at grazing : 7,090kg in 20-25cm 7,882kg in 30-35n and 8,260 kgha in 40-45cm of height. Higher DM was observed at medium grazing intensity. In spring, daily DM production was more vigorous than those in summer and autumn season. Cmde protein (CP), digestible DM, and DM intake were decreased with increasing of plant height at grazing. CP content was 25.8% in 20-25cm 22.4% in 30-35m and 19.2% in 40-45cm, while the contents of neutral detergent fiber and acid detergent fiber were increased with higher plant height. Relative feed value was 11 1.2 in 20-25cm, 104.4 in 30-35n and 99.6 in 40-45cm. Also nutritive value of pre-grazing pasture plants was remarkably higher than that of post-grazing, and not significant differences of nutritive value were found between grazing intensity. From the above mults, it may be concluded that optimum plant height for grazing was 20-25cm and 30- 35cm in pasture mixtures dominated by orchardgms, and medium grazing intensity was very desirable for pasture productivity.