Blasi D A, Ward J K, Klopfenstein T J, Britton R A
University of Nebraska, Lincoln 68583-0908.
J Anim Sci. 1991 Jun;69(6):2294-302. doi: 10.2527/1991.6962294x.
Grazing trials were conducted utilizing individually supplemented lactating beef cows in a 2-yr study to determine the effect of supplemental escape protein (EP) on cow/calf performance during the active growth periods of smooth brome and big bluestem. Graded levels (0, .11, .23, and .34 kg of EP/animal from an equal-protein-basis mixture of blood meal and corn gluten meal were offered daily, replacing corn starch and molasses, which was used as the energy control. All cows received 582 g of supplemental DM/d. Analyses for the smooth brome study indicated a cubic response (P less than .05) to milk production and calf daily gain. No response to EP supplementation (P greater than .10) was observed for the big bluestem study. Analysis of esophageal extrusa samples collected throughout the grazing seasons for both years demonstrated that quality of forage selected by the animal decreased as the trial progressed. Using a 16-h modified dacron bag technique that did not adjust for microbial attachment, protein escaping degradation for smooth brome and big bluestem was estimated to range from 7.0 to 14.5% and 22.2 to 30.3%, respectively. There was limited response to a moderate level of EP supplementation of lactating cows grazing smooth brome, but calf gains were depressed by both the low and the high levels of EP. Lactating cows grazing big bluestem did not respond to EP supplementation, but added energy supplement depressed calf gains.
在一项为期两年的研究中，对个体补饲的泌乳期肉牛进行了放牧试验，以确定补充逃逸蛋白（EP）对在草地早熟禾和大须芒草活跃生长期间母牛/犊牛生产性能的影响。从血粉和玉米蛋白粉的等蛋白基础混合物中，每天提供分级水平（0、0.11、0.23和0.34千克EP/头），替代用作能量对照的玉米淀粉和糖蜜。所有母牛每天接受582克补充干物质。草地早熟禾研究分析表明，对产奶量和犊牛日增重呈三次方反应（P小于0.05）。在大须芒草研究中，未观察到对补充EP的反应（P大于0.10）。对两年放牧季节收集的食管外排物样本分析表明，随着试验进展，动物选择的牧草质量下降。使用未对微生物附着进行调整的16小时改良涤纶袋技术，草地早熟禾和大须芒草未降解而逃逸的蛋白质估计分别为7.0%至14.5%和22.2%至30.3%。放牧草地早熟禾的泌乳母牛对中等水平的EP补充反应有限，但低水平和高水平的EP均使犊牛增重下降。放牧大须芒草的泌乳母牛对EP补充无反应，但添加能量补充剂使犊牛增重下降。
