The effect of stocking rate on herbage utilization under time-restricted grazing by lactating dairy cows
1997
Nonaka, I. (Hokkaido Univ., Sapporo (Japan). Faculty of Agriculture) | Furukawa, K. | Hashimoto, N. | Tokita, K. | Nakatsuji, H. | Okubo, M. | Asahida, Y.
Effect of stocking rate on herbage utilization were studied in lactating Holstein cows. Cows (average BW = 5944 kg, days in milk = 47.2) were divided into two stocking rates; L = five cows/ha, and H = seven cows/ha. Cows were allowed to graze 5 hours daily from May to October of 1993 and 1994 at Experimental Farm, Hokkaido University, under time-restricted grazing system. Total numbers of cows grazed in 1993 and 1994 were : L = 825 and 828, and H = 1062 and 1153, respectively. In 1993, daily herbage utilization was almost equal in both groups (51 to 53 kg DM/ha), but the annual herbage utilization of H was lower than L (7.9 vs. 9.1 tDM/ha). Higher stocking rate in 1993 reduced sward \height (8 to 17 cm). This might be due to the shorter grazing cycle for H during spring of 1993 (4 to 8 days) compared to L (12 to 22 days). Also, total number of grazing days was shorter for H compared to L (156 vs. 171 days). However, there was no difference between annual herbage utilization of H and L (9.9 vs. 9.6 tDM/ha) in1994, when herbage was utilized in proportion to the seasonal changes of daily herbage production
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