Department of Animal Science, Texas A&M University, College Station, TX 77843, USA.
Novonesis, Hørsholm, 2970, Denmark.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skae209.
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.
本实验评估了在 90 天放牧期间接受基于芽孢杆菌的益生菌的高危育肥牛的性能、健康和生理反应。该实验共使用了 240 头 Angus 影响的育肥牛，该实验在 2 年内重复进行（每年 120 头）。每年，从拍卖场获得育肥牛并运送到实验设施（120 公里）。育肥牛到达时（第-1 天）记录体重（BW），并将该值与第 0 天记录的 BW 平均值表示初始 BW（236.6±1.5kg）。第 0 天，根据 BW 对育肥牛进行排名，并将其分配到 12 个具有储备原生草的牧场之一（4 公顷牧场；每牧场 10 头育肥牛）。牧场随机分配接受每日补充干酒糟，添加量为 BW 的 1%，其中含有：1）枯草芽孢杆菌+地衣芽孢杆菌益生菌（BOV；每头育肥牛每天 Bovacillus2g；Novonesis，Horsholm，丹麦）或 2）无饲料添加剂（CON）。除了自由选择水和矿物质+维生素混合物外，育肥牛还接受了治疗，其中不包含离子载体。育肥牛从第 0 天到第 90 天接受治疗，此外，还接受了 16 小时的饲料和水限制后的收缩 BW 评估，并使用 4%的铅笔收缩来计算最终 BW。根据初始和最终 BW 计算平均日增重（ADG）。未检测到处理对育肥牛最终 BW 和 ADG 的影响（P≥0.73）。处理×天的交互作用（P≤0.05）检测到血浆触珠蛋白浓度的差异，CON 育肥牛在第 14 天和第 28 天的浓度更高（P≤0.02）。BRD 体征的发生率在处理之间没有差异（P=0.97）（BOV 和 CON 分别为 51.7%和 51.3%；SEM=7.70）。然而，CON 组的育肥牛死亡率+因健康并发症而被移除的比例高于 BOV 组（0.00%比 5.04%；SEM=1.41）。补充 BOV 提高了（P≤0.04）基于牧场的总活体增重变化（分别为 643 比 502kg/牧场，SEM=45）和基于牧场的最终总活体重量（分别为 3007 比 2869kg/牧场，SEM=46）。总的来说，向高危育肥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，也没有提高 ADG，但减少了急性期蛋白反应，降低了育肥牛死亡率+移除率，并提高了 90 天放牧期间基于牧场的生产力。
