Abstract: The effect of two grazing system (continuous grazing (CG)and rotational grazing (RG)) and three grazing intensities (HGI (0.467 ha/cow), MGI (0.667 ha/cow), and LGI (0.867ha/cow )) on the herbage intake, diet composition, nutrient ingestion for Friesian cows at middle lactation grazed in mixed sward of perennial ryegrass (Lolium perenne) and white clover (Trtheium repens) were studied at Nanshan Ranch, Hunan Province.The herbage intake for RG cows was lower than that for CG cows, but the proportion of ryegrass and white clover in the diet for RG cows is higher than that for CG cows, so the daily ingestion of CP, GE, Ca and P for RG cows were higher than those for CG cows.The herbage intake, ingestion of CP, ADF,GE,Ca and P raised slightly with the increment of grazing intensity, but there was no significant difference between grazing intensities.The higher proportion of perennial ryegrass and white clove and lower proportion of dead herbage and weed were existed when grazing intensity increased.It is indicated that grazing system and grazing intensity have a little effect on herbage intake, ingestion of CP,ADF,GE,calcium and phosphorus for dairy cows.

Key words: Grazing system, Grazing intensity, Dairy cow, Herbage intake

摘要： 本文作者在湖南南山牧场研究了两种放牧制度(分区轮牧和连续放牧)和三种放牧强度(0.467,0.667和0.867ha/头)对处于泌乳中后期的黑白花奶牛在多年生黑麦草/由三叶人工草地上的放牧来食量、采食植物组成、营养摄入量的影响。结果表明:轮牧制奶牛的采食量低于连续放牧制,但其口粮组成中黑麦草和白三叶的比例高于连续放牧,故粗蛋白质、总能、钙和磷的日摄入量也低于轮牧制奶牛。随放牧强度的增加,奶牛的来食量、以及粗蛋白质、酸性洗涤纤维、总能、钙和磷的摄入量均有所增加,但三种放牧强度间差异并不显著。放牧强度越大,家畜日粮组成中黑麦草和白三叶的比例越大,而枯草和杂草所占比例越小。这说明在南山试验条件下,放牧制度和放牧强度对奶牛的采食量及各种营养物质的日摄入量有一定影响。

关键词: 放牧制度, 放牧强度, 奶牛, 采食量, 营养摄入量