Reid R L, Puoli J R, Jung G A, Cox-Ganser J M, McCoy A
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown 26506.
J Anim Sci. 1994 Jul;72(7):1823-31. doi: 10.2527/1994.7271823x.
Four years of grazing trials were conducted with Brassica forages to evaluate their chemical composition and effect on ADG of fattening lambs and breeding ewes in late fall. Brassicas tested included kales (Brassica oleracea L. var. acephala DC), turnips (B. rapa L.), and a chinese cabbage hybrid (B. rapa L. x B. pekinensis [Lour.] Rupr.). Daily gains of lambs varied widely among years (19 to 330 g/d); ADG on Brassicas were, however, generally higher than on stockpiled Kentucky 31 tall fescue (Festuca arundinacea Schreb.) or orchardgrass (Dactylis glomerata L.)-red clover (Trifolium pratense L.) pastures grazed at the same time. In 1 yr, dietary supplementation of lambs grazing a hybrid turnip (Forage Star) with iodine and copper oxide needles improved (P < .05) ADG; however, there was no effect on gains in two later years. In 2 yr, lambs showed higher ADG on Tyfon chinese cabbage hybrid (241 and 330 g/d) than on Forage Star turnip (197 and 275 g/d) or stockpiled grass-clover (135 and 233 g/d), but yield of Tyfon was lower. Indications that supplementary hay improved ADG of lambs and ewes were not confirmed in the final year, in which hay increased (P < .05) ADG of lambs in the first 3 wk of grazing Brassicas but decreased gains later. Thyroid weights were increased (P < .01) consistently in all trials on Brassicas, but enlargement was modest and not related to ADG. Brassica forages provided high yields (5.6 to 10.5 t/ha) of DM in the late fall to early winter period, with high carrying capacity for sheep but large variability in ADG.
进行了为期四年的以芸苔属牧草为对象的放牧试验，以评估其化学成分以及对深秋育肥羔羊和繁殖母羊平均日增重（ADG）的影响。所测试的芸苔属植物包括羽衣甘蓝（Brassica oleracea L. var. acephala DC）、芜菁（B. rapa L.）和一种大白菜杂交种（B. rapa L. x B. pekinensis [Lour.] Rupr.）。各年份羔羊的日增重差异很大（19至330克/天）；然而，在芸苔属植物上的平均日增重通常高于同时放牧的肯塔基31号高羊茅（Festuca arundinacea Schreb.）或果园草（Dactylis glomerata L.）-红三叶（Trifolium pratense L.）储备草场。在1年中，对放牧杂交芜菁（饲料之星）的羔羊进行碘和氧化铜针剂的日粮补充提高了（P < .05）平均日增重；然而，在随后两年对增重没有影响。在2年中，羔羊在泰丰大白菜杂交种上的平均日增重（241和330克/天）高于饲料之星芜菁（197和275克/天）或储备草-三叶草（135和233克/天），但泰丰的产量较低。补充干草能提高羔羊和母羊平均日增重的迹象在最后一年未得到证实，在该年中，干草在放牧芸苔属植物的前3周提高了（P < .05）羔羊的平均日增重，但随后降低了增重。在所有芸苔属植物试验中，甲状腺重量均持续增加（P < .01），但肿大程度适中且与平均日增重无关。芸苔属牧草在深秋至初冬期间提供了高产（5.6至10.5吨/公顷）的干物质，对绵羊的承载能力高，但平均日增重差异很大。
