This experiment evaluated the performance, health, and physiological responses of high-risk steers receiving a Bacillus-based probiotic during a 90-d grazing period. A total of 240 Angus-influenced steers were used in this experiment that was replicated over 2 yr (120 steers/year). Each year, steers were obtained from an auction yard and transported to the experimental facility (120 km). Steer body weight (BW) was recorded at arrival (day −1), and this value was averaged with BW recorded on day 0 to represent the initial BW (236.6 ± 1.5 kg). On day 0, steers were ranked by BW and allocated to 1 of 12 pastures with stockpiled native grass (4-ha pastures; 10 steers/pasture). Pastures were randomly assigned to receive daily supplementation with dried distillers’ grains at 1% of BW containing either: 1) Bacillus subtilis + B. licheniformis probiotic (BOV; 2 g/steer daily of Bovacillus; Novonesis, Horsholm, Denmark) or 2) no feed additive (CON). Cattle received treatments from days 0 to 90, in addition to free-choice access to water and mineral + vitamin mix without ionophore. Steers were assessed for bovine respiratory disease (BRD) signs daily. Blood samples were collected and full BW was recorded on days 0, 14, 28, 56, and 90. Shrunk BW was recorded on day 91 after 16 h of feed and water restriction, and a 4% pencil shrink was used to calculate the final BW. Average daily gain (ADG) was calculated based on initial and final BW. No treatment effects were detected (P ≥ 0.73) for steer final BW and ADG. A treatment × day interaction was detected (P ≤ 0.05) for plasma haptoglobin concentration, which was greater for CON steers on days 14 and 28 (P ≤ 0.02). Incidence of BRD signs did not differ (P = 0.97) between treatments (51.7% and 51.3% for BOV and CON, respectively; SEM = 7.70). However, steer mortality + removals for health complications were greater (P = 0.01) in CON compared to BOV (0.00% vs. 5.04%, respectively; SEM = 1.41). Supplementing BOV improved (P ≤ 0.04) total pasture-based liveweight change (643 vs. 502 kg/pasture, respectively; SEM = 45) and final pasture-based total liveweight (3,007 vs. 2,869 kg/pasture, respectively; SEM = 46). Collectively, supplementation with a probiotic based on B. subtilis and B. licheniformis to high-risk stocker cattle did not alleviate the incidence of BRD signs nor improved ADG, but decreased acute-phase protein response, reduced steer mortality + removal, and increased pasture-based productivity during a 90-d grazing period.

中文翻译：

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为高风险饲养牛补充基于芽孢杆菌的益生菌


该实验评估了在 90 天放牧期间接受基于芽孢杆菌的益生菌的高危公牛的性能、健康和生理反应。本实验共使用了 240 头受安格斯影响的公牛，并在 2 年内复制（120 头公牛/年）。每年，从拍卖场获得公牛并运送到实验设施（120 公里）。在到达时（第 -1 天）记录阉牛体重 （BW），该值与第 0 天记录的 BW 取平均值，以表示初始体重 （236.6 ± 1.5 kg）。第 0 天，按 BW 对公牛进行排名，并将其分配到 12 个储存了原生草的牧场中的 1 个（4 公顷牧场;10 头公牛/牧场）。牧场被随机分配接受每日补充 1% BW 的干酒糟，其中含有：1） 枯草芽孢杆菌 + B. licheniformis 益生菌（BOV;每天 2 克/阉牛的 Bovacillus;Novonesis，丹麦 Horsholm）或 2） 无饲料添加剂 （CON）。牛从第 0 天到第 90 天接受治疗，此外还可以自由选择水和矿物质 + 维生素混合物，不含离子载体。每天评估阉牛呼吸道疾病 （BRD） 体征。收集血样，并在第 0 、 14 、 28 、 56 和 90 天记录全 BW。在饲喂和饮水限制 16 小时后，在第 91 天记录收缩的 BW，并使用 4% 的铅笔收缩来计算最终 BW。平均每日增益 （ADG） 是根据初始和最终 BW 计算的。未检测到对阉牛最终 BW 和 ADG 的治疗效果 （P ≥ 0.73）。检测到血浆结合珠蛋白浓度的处理×相互作用 （P ≤ 0.05），CON 阉牛在第 14 天和第 28 天表现出更高的相互作用 （P ≤ 0.02）。BRD 体征的发生率在治疗之间没有差异 （P = 0.97） （51.7% 和 51.BOV 和 CON 分别为 3%;SEM = 7.70）。然而，与 BOV 相比，CON 的阉牛死亡率 + 健康并发症的移除率更高 （P = 0.01） （分别为 0.00% 和 5.04%;SEM = 1.41）。补充 BOV 改善了 （P ≤ 0.04） 基于牧场的总活重变化（分别为 643 和 502 公斤/牧场;SEM = 45）和基于最终牧场的总活重（分别为 3,007 和 2,869 公斤/牧场;SEM = 46）。总的来说，向高风险放牧牛补充基于枯草芽孢杆菌和地衣芽孢杆菌的益生菌并没有减轻 BRD 体征的发生率，也没有改善 ADG，但降低了急性期蛋白质反应，降低了阉牛死亡率 + 清除，并提高了 90 天放牧期间基于牧场的生产力。