Meyer N F, Erickson G E, Klopfenstein T J, Greenquist M A, Luebbe M K, Williams P, Engstrom M A
Department of Animal Science, University of Nebraska, Lincoln, NE 68583, USA.
J Anim Sci. 2009 Jul;87(7):2346-54. doi: 10.2527/jas.2008-1493. Epub 2009 Apr 9.
A feedlot (Exp. 1) experiment was conducted to evaluate the effects of an essential oil mixture (EOM), experimental essential oil mixture (EXP), tylosin, and monensin (MON) on performance, carcass characteristics, and liver abscesses. A metabolism experiment (Exp. 2) was conducted to evaluate the effects of EOM, EXP, and MON on ruminal fermentation and digestibility in finishing steers. In Exp. 1, 468 yearling steers (398 +/- 34 kg initial BW) were used in 50 pens (10 pens/treatment) and received their respective dietary treatments for 115 d. Five dietary treatments were compared in Exp. 1: 1) control, no additives (CON); 2) EOM, 1.0 g/steer daily; 3) EXP, 1.0 g/steer daily; 4) EOM, 1.0 g/steer daily plus tylosin, 90 mg/steer daily (EOM+T); and 5) monensin, 300 mg/steer daily plus tylosin, 90 mg/steer daily (MON+T). Compared with CON, steers fed MON+T had decreased DMI (P < 0.01), and steers fed EOM+T and MON+T had improved G:F (P </= 0.02). Average daily gain was not different among treatments (P > 0.58). There was a trend (P = 0.09) for a treatment effect on 12th-rib fat thickness, which resulted in a significant increase in calculated yield grade for the EOM+T treatment. No other carcass characteristics were affected by treatment (P >/= 0.10). Prevalence of total liver abscesses was reduced for steers fed tylosin compared with no tylosin (P < 0.05). In Exp. 2, 8 ruminally fistulated steers (399 +/- 49 kg initial BW) were assigned randomly to 1 of 4 treatments in a replicated 4 x 4 Latin square designed experiment. Treatments were 1) CON, 2) EOM, 3) EXP, and 4) MON with feeding rates similar to Exp. 1. There were no differences in DMI, OM intake, and apparent total tract DM or OM digestibilities among treatments (P > 0.30). Feed intake patterns were similar among feed additive treatments (P > 0.13). Total VFA (P = 0.10) and acetate (P = 0.06) concentrations tended to be affected by treatment with EOM numerically greater than CON. Average ruminal pH ranged from 5.59 to 5.72 and did not differ among treatments. Addition of a EOM or monensin to a diet containing tylosin improves G:F, but little difference was observed in metabolism or digestibility.
进行了一项饲养场试验（试验1），以评估精油混合物（EOM）、试验性精油混合物（EXP）、泰乐菌素和莫能菌素（MON）对育肥牛生产性能、胴体特性和肝脓肿的影响。进行了一项代谢试验（试验2），以评估EOM、EXP和MON对育肥牛瘤胃发酵和消化率的影响。在试验1中，468头一岁育肥牛（初始体重398±34千克）被饲养在50个栏中（每个处理10个栏），并接受各自的日粮处理115天。试验1中比较了五种日粮处理：1）对照，无添加剂（CON）；2）EOM，每头每天1.0克；3）EXP，每头每天1.0克；4）EOM，每头每天1.0克加泰乐菌素，每头每天90毫克（EOM+T）；5）莫能菌素，每头每天300毫克加泰乐菌素，每头每天90毫克（MON+T）。与CON相比，饲喂MON+T的育肥牛干物质采食量降低（P<0.01），饲喂EOM+T和MON+T的育肥牛料重比提高（P≤0.02）。各处理间平均日增重无差异（P>0.58）。在第12肋处脂肪厚度上存在处理效应趋势（P=0.09），这导致EOM+T处理的计算产肉等级显著提高。其他胴体特性不受处理影响（P≥0.10）。与未添加泰乐菌素的育肥牛相比，添加泰乐菌素的育肥牛总肝脓肿患病率降低（P<0.05）。在试验2中，8头瘤胃造瘘育肥牛（初始体重399±49千克）被随机分配到重复4×4拉丁方设计试验的4种处理中的1种。处理为：1）CON，2）EOM，3）EXP，4）MON，饲喂量与试验1相似。各处理间干物质采食量、有机物摄入量以及表观全肠道干物质或有机物消化率无差异（P>0.30）。饲料添加剂处理间的采食量模式相似（P>0.13）。总挥发性脂肪酸（P=0.10）和乙酸（P=0.06）浓度在数值上倾向于受EOM处理影响且大于CON。平均瘤胃pH值在5.59至5.72之间，各处理间无差异。在含泰乐菌素的日粮中添加EOM或莫能菌素可提高料重比，但在代谢或消化率方面观察到的差异较小。
