Department of Animal Science, University of California, Davis 95616, USA.
J Anim Sci. 2009 Dec;87(12):4101-8. doi: 10.2527/jas.2009-1959. Epub 2009 Sep 11.
Two trials were conducted to evaluate the influence of virginiamycin supplementation on growth performance and digestive function. In trial 1, 144 Holstein steer calves (119 kg of initial BW) were used in a 340-d trial. Treatments were (DM basis) 1) control (no antibiotic); 2) 16 mg/kg of virginiamycin; 3) 22.5 mg/kg of virginiamycin; and 4) 28 mg/kg of monensin. Calves received a steam-flaked corn-based growing diet for the first 112 d and thereafter were fed a finishing diet from d 112 until slaughter. Steers were divided into 2 BW groups (lighter-half and heavier-half), and assigned within groups to 24 pens (6 steers/pen). Virginiamycin did not affect (P > 0.20) ADG, but increased 340-d G:F (linear; P = 0.02) and dietary NE (linear; P = 0.04). Improvements in dietary NE were most pronounced during the final 116 d of the feeding period (linear; P = 0.04) that comprised the hot summer months (June through September). Monensin did not affect (P > 0.20) growth performance or dietary NE. Although average initial BW of the lighter-half and heavier-half BW groups differed by only 4 kg, the heavier BW group had greater HCW (13 kg, P = 0.02), LM area (5.4%, P = 0.01), ADG (4.3%, P = 0.02), G:F (2.3%, P = 0.08), and dietary NE (3.2%. P = 0.01) than the lighter BW group. In trial 2, 4 Holstein steers (269 +/- 3.5 kg) with cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design to evaluate treatment effects on digestion. Virginiamycin did not affect (P > 0.20) ruminal digestion of OM, NDF, starch, and N, and microbial efficiency, but tended to linearly increase (P = 0.09) ruminal N efficiency (nonammonia N flow to the small intestine/N intake). Likewise, virginiamycin did not affect (P > 0.20) postruminal or total tract digestion of OM, starch, NDF, and N. Compared with the control diet, monensin depressed total tract digestion of OM (4.2%, P = 0.03) and NDF (29.5%, P = 0.02). There were no treatment effects (P > 0.20) on ruminal pH, or ruminal lactate and total VFA molar concentration. Virginiamycin increased ruminal molar proportion of acetate (quadratic; P = 0.04) and estimated methane production (quadratic; P = 0.07), and decreased propionate molar proportion (quadratic; P = 0.09). Monensin did not affect (P > 0.20) ruminal VFA molar proportions or estimated methane production. We concluded that virginiamycin supplementation can enhance feedlot growth-performance and dietary energetic efficiency of calf-fed Holstein steers.
两项试验旨在评估维吉尼亚霉素添加对生长性能和消化功能的影响。在试验 1 中，144 头荷斯坦公牛犊（初始体重 119kg）进行了 340 天的试验。处理为（DM 基础）1）对照（无抗生素）；2）16mg/kg 维吉尼亚霉素；3）22.5mg/kg 维吉尼亚霉素；4）28mg/kg 莫能菌素。犊牛在第 112 天之前接受蒸汽压片玉米基础生长日粮，此后从第 112 天开始接受育肥日粮直至屠宰。公牛犊分为 2 个 BW 组（较轻一半和较重一半），并在组内分配到 24 个围栏（6 头/围栏）。维吉尼亚霉素不影响（P＞0.20）ADG，但提高了 340 天的 G:F（线性；P＝0.02）和饲粮 NE（线性；P＝0.04）。在饲养期的最后 116 天（线性；P＝0.04），即包括炎热的夏季（6 月至 9 月）在内，饲粮 NE 的改善最为明显。莫能菌素不影响（P＞0.20）生长性能或饲粮 NE。虽然较轻一半和较重一半 BW 组的平均初始 BW 仅相差 4kg，但较重 BW 组的 HCW（13kg，P＝0.02）、LM 面积（5.4%，P＝0.01）、ADG（4.3%，P＝0.02）、G:F（2.3%，P＝0.08）和饲粮 NE（3.2%，P＝0.01）更高。在试验 2 中，4 头荷斯坦公牛（269±3.5kg）具有瘤胃和近端十二指肠的套管，采用 4×4 拉丁方设计评估处理对消化的影响。维吉尼亚霉素不影响（P＞0.20）瘤胃 OM、NDF、淀粉和 N 的消化，也不影响微生物效率，但倾向于线性增加（P＝0.09）瘤胃 N 效率（非氨氮流向小肠/N 摄入量）。同样，维吉尼亚霉素不影响（P＞0.20）瘤胃后或全肠道 OM、淀粉、NDF 和 N 的消化。与对照日粮相比，莫能菌素降低了 OM（4.2%，P＝0.03）和 NDF（29.5%，P＝0.02）的全肠道消化。处理间无影响（P＞0.20）瘤胃 pH 或瘤胃乳酸和总 VFA 摩尔浓度。维吉尼亚霉素增加了瘤胃乙酸摩尔比例（二次；P＝0.04）和估计的甲烷产生（二次；P＝0.07），并降低了丙酸摩尔比例（二次；P＝0.09）。莫能菌素不影响（P＞0.20）瘤胃 VFA 摩尔比例或估计的甲烷产生。我们得出结论，维吉尼亚霉素添加可以提高犊牛喂养的荷斯坦公牛的生长性能和饲料能量效率。
