摘要
Six ruminally fistulated midlactating multiparous Holstein cows were used in a double 3 × 3 Latin square design (35-d periods) to study the effects of lasalocid (LAS) and monensin (MON) supplemented at 24 mg/kg of dry matter on digestion, ruminal fermentation, blood metabolites, and milk production. Cows were blocked according to milk production and fed a red clover silage-based total mixed ration (17.8% crude protein) without supplementation or supplemented with LAS or MON. Daily dry matter intake, milk production, and milk fat and protein concentrations were similar among treatments and averaged 23.5 kg, 36.6 kg, 3.36%, and 3.38%, respectively. Rumen lipogenic:glucogenic volatile fatty acids and NH3-N concentration were lower, and apparent digestibility of dry matter, organic matter, crude protein, and gross energy were higher with than without ionophore supplementation. Compared with LAS, MON increased concentrations of plasma urea-N and milk urea-N, and excretion of urinary urea-N and total N. Monensin also decreased N retention and tended to reduce plasma concentration of nonessential AA in comparison with LAS. Both ionophores reduced daily fecal excretion of N by 13 g compared with the control, but MON increased daily losses of urinary N by 36 g compared with LAS. Results from this study suggest that postabsorptive metabolism of N might be altered by the type of ionophore fed.
摘要译文
多胎荷斯坦奶牛以双3×3拉丁方设计（35天时间段）使用，以研究以24 mg / kg干物质补充的拉沙里菌素（LAS）和莫能菌素（MON）对消化的影响，瘤胃发酵，血液代谢产物和产奶量。根据牛奶产量阻断奶牛并饲喂基于青贮饲料的红三叶草总混合日粮（17。8％粗蛋白），无需补充或补充LAS或MON。每日干物质摄入量，产奶量，各处理间乳脂和蛋白质浓度相似，平均分别为23.5 kg，36.6 kg，3.36％和3.38％。瘤胃脂肪生成：生成葡萄糖的挥发性脂肪酸和NH 3 -N浓度较低，干物质，有机物，粗蛋白的表观消化率，与没有离子载体补充相比，总能量更高。与LAS相比，MON增加了血浆尿素-N和牛奶尿素氮的浓度，以及尿尿素氮和总氮的排泄。与LAS相比，莫能菌素还降低了N保留并倾向于降低非必需AA的血浆浓度。与对照相比，两种离子载体均使每日粪便排泄N减少13 g，但与LAS相比，MON每日尿N减少36 g。这项研究的结果表明N的吸收后代谢可能会被喂养的离子载体的类型改变。
R.Martineau[*];C.Benchaar[†];H.V.Petit[†];H.Lapierre[†];D.R.Ouellet[†];D.Pellerin[*];R.Berthiaume[†];. Effects of Lasalocid or Monensin Supplementation on Digestion, Ruminal Fermentation, Blood Metabolites, and Milk Production of Lactating Dairy Cows1[J]. Journal of Dairy Science, 2007,90(12): 5714-5725