Bargo F, Muller L D, Varga G A, Delahoy J E, Cassidy T W
Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802, USA.
J Dairy Sci. 2002 Nov;85(11):2964-73. doi: 10.3168/jds.S0022-0302(02)74382-8.
Six multiparous Holstein cows fitted with rumen cannulas were used to study the effect of three feeding systems combining pasture and total mixed rations (TMR) on ruminal digestion in a 21-wk repeated measures experiment. The three treatments were: 1) pasture plus concentrate (PC), 2) pasture plus partial TMR (pTMR), and 3) TMR (nonpasture). Ruminal NH3-N concentration was lower on both the pTMR and TMR treatments (10.2 +/- 0.5 mg/dL) than on the PC treatment (19.9 +/- 0.5 mg/dL). Ruminal pH was not affected by treatments and averaged 5.87. Neither total volatile fatty acid concentration (137.5 mmol/L) nor individual volatile fatty acid proportions (63.1,20.6, and 12.0 mol/ 100 mol for acetate, propionate, and butyrate, respectively) differed among treatments. The pTMR treatment reduced the total potentially degradable fraction of dry matter (85.5 vs. 82.3%) and the potentially digestible fraction of neutral detergent fiber (82.1 vs. 74.9%) of pasture compared to the PC treatment. Ruminal NH3-N losses were reduced when combining pasture and TMR; however this combination decreased the ruminal digestion of pasture, indicating the presence of associative effects in the rumen.
在一项为期21周的重复测量实验中，选用6头装有瘤胃瘘管的经产荷斯坦奶牛，研究三种结合牧场放牧和全混合日粮（TMR）的饲养系统对瘤胃消化的影响。三种处理方式分别为：1）牧场放牧加精料（PC）；2）牧场放牧加部分全混合日粮（pTMR）；3）全混合日粮（不放牧）。pTMR和TMR处理组的瘤胃NH₃-N浓度（10.2±0.5mg/dL）均低于PC处理组（19.9±0.5mg/dL）。瘤胃pH不受处理方式影响，平均为5.87。各处理组间总挥发性脂肪酸浓度（137.5mmol/L）及各挥发性脂肪酸比例（乙酸、丙酸和丁酸分别为63.1、20.6和12.0mol/100mol）均无差异。与PC处理相比，pTMR处理降低了牧场放牧牧草干物质的总潜在可降解部分（85.5%对82.3%）和中性洗涤纤维的潜在可消化部分（82.1%对74.9%）。将牧场放牧与全混合日粮相结合时，瘤胃NH₃-N损失减少；然而，这种组合降低了牧场放牧牧草的瘤胃消化率，表明瘤胃中存在协同效应。
