Hill G M, Gates R N, Burton G W
Department of Animal and Dairy Science, University of Georgia, Coastal Plain Station, Tifton 31793-0748.
J Anim Sci. 1993 Dec;71(12):3219-25. doi: 10.2527/1993.71123219x.
A new high-yielding bermudagrass hybrid, Tifton 85, produced 26% higher DM yield (P = .05) with 11% higher IVDMD (P = .05) than Coastal in two 3-yr yield trials. Tifton 78 and Tifton 85 were established in duplicate .81-ha pastures in 1988 and were grazed during 1989, 1990, and 1991 using a variable stocking rate method. Four tester steers per pasture with 269 kg initial BW grazed continuously for 169 d/yr beginning in April. Forage mass, targeted at 2,800 kg of DM/ha, was maintained by adjusting stocking rates at 14-d intervals to correspond with ground-level forage samples taken at 14-d intervals. Pastures received 84 kg of N/ha in March, June, and August of each year. Nutritive value was assessed using whole masticate samples from two esophageal cannulated steers grazing each pasture in late May, mid-July, or early September. The 3-yr mean masticate analyses revealed similar CP for Tifton 78 and Tifton 85 in May and July, but higher (P < .05) CP for Tifton 85 than for Tifton 78 in September. The IVDMD was higher (P < .05) in May and September for Tifton 85 than for Tifton 78; and, mean and medium particle sizes were greater (P < .05) for Tifton 85 than for Tifton 78 in May, July, and September samples.(ABSTRACT TRUNCATED AT 250 WORDS)
一种新的高产百慕大草杂交种Tifton 85，在两项为期3年的产量试验中，其干物质产量比Coastal高26%（P = 0.05），体外干物质消化率高11%（P = 0.05）。Tifton 78和Tifton 85于1988年在两块面积为0.81公顷的重复牧场上建植，并在1989年、1990年和1991年采用可变载畜率方法放牧。每个牧场有4头初始体重为269千克的试验阉牛，从4月开始每年连续放牧169天。通过每14天调整载畜率以对应每14天采集的地面牧草样本，将牧草质量维持在目标水平2800千克干物质/公顷。每年3月、6月和8月，牧场每公顷施氮84千克。在5月下旬、7月中旬或9月初，从每块牧场放牧的两头安装食管瘘管的阉牛采集全咀嚼样本，以此评估营养价值。3年的平均咀嚼分析结果显示，5月和7月Tifton 78和Tifton 85的粗蛋白含量相似，但9月Tifton 85的粗蛋白含量高于Tifton 78（P < 0.05）。5月和9月，Tifton 85的体外干物质消化率高于Tifton 78（P < 0.05）；在5月、7月和9月的样本中，Tifton 85的平均粒径和中值粒径大于Tifton 78（P < 0.05）。（摘要截短于250词）
