Gruber Cody E, Snider Miriam A, Johnson Michelle L, Hess Tom, Kegley Elizabeth B, Rivera J Daniel, Mitchell James L, Gadberry M Shane
Livestock and Forestry Research Station, University of Arkansas, Division of Agriculture, Batesville, AR 72501, USA.
Department of Animal Science, University of Arkansas System Division of Agriculture, Fayetteville, AR 72701, USA.
Transl Anim Sci. 2025 Aug 28;9:txaf116. doi: 10.1093/tas/txaf116. eCollection 2025.
With the continued increase of fertilizer prices, stocker cattle producers may utilize alternative management strategies to mitigate costs and extend the grazing season to achieve better utilization of a wheat ( L.) crop. One potential strategy is to reduce pasture nitrogen () fertilization rates combined with animal dietary supplementation. In this 3-year () study, wheat pastures (1.62-hectare ()) were stocked at fixed rates of 2.47 and 4.94 steer/ha in the fall and spring respectively. Nitrogen was applied as urea to experimental pastures at three different rates: 1) 100.9 (), 2) 134.5 (), and 3) 168.1 kg N/ha (). These pastures were compared to pastures with a N application rate of 100.9 kg N/ha stocked with steer calves supplemented dried distillers grains plus solubles () at 1.0% body weight (; ). In the spring, 100S pastures produced greater ( ≤ 0.05) mean and final forage mass (), as well as the greatest slope change in FM. Fall average daily gain () was decreased ( ≤ 0.05) in 168N pastures, while 100S produced greater ( ≤ 0.001) spring grazing days (), weight gain/ha, and final BW. Both 100S and 168N produced a greater ( 0.05) number of combined grazing d, with 100S yielding an additional 13 d. Additionally, steers assigned to the 100S treatment produced greater ( ≤ 0.001) combined weight gain/ha. Blood urea nitrogen () concentrations on D28 were greater ( ≤ 0.001) for steers on 100S pastures and were slightly in excess of the range for maximized growth. Total spring income/ha was greater ( ≤ 0.05) for 100S and 168N, with 100S making an extra $82.38/ha compared to 100N. Calf management and feed costs were greater ( 0.001) for 100S and resulted in an increase of costs $514.60/ha above 100N. Net returns were greater ( ≤ 0.05) for 100N and 135N, with 100N netting the greatest returns, which averaged $361.00/ha more than the net return for 100S due to feed costs. Due to a substitution effect, an additional 525 kg dry matter ()/ha of FM was available, indicating that pastures could be stocked with an additional steer for every 2.81 ha increase in 100S pasture size, potentially providing additional economic benefits. Results from this study indicate that while DDGS supplementation provided benefits to steer and pasture performance in the spring, it was not beneficial to overall economics within the scope of the research scale production system.
随着肥料价格持续上涨，架子牛养殖户可能会采用替代管理策略来降低成本，并延长放牧季节，以更好地利用小麦作物。一种潜在策略是降低牧场氮肥施用量并结合动物日粮补充。在这项为期3年的研究中，秋季和春季分别以每公顷2.47头和4.94头架子牛的固定放养率在1.62公顷的小麦牧场上放牧。将尿素以三种不同施用量施用于试验牧场：1）100.9千克氮/公顷，2）134.5千克氮/公顷，3）168.1千克氮/公顷。将这些牧场与施氮量为100.9千克氮/公顷且补饲干酒糟及其可溶物（DDGS）量为体重1.0%的架子牛犊放牧的牧场进行比较。春季，施氮量100.9千克氮/公顷的牧场（100S）产生了更高（P≤0.05）的平均和最终牧草质量，以及最大的牧草质量斜率变化。168N牧场秋季平均日增重（ADG）降低（P≤0.05），而100S产生了更多（P≤0.001）的春季放牧天数、每公顷体重增加量和最终体重。100S和168N的总放牧天数都更多（P＞0.05），100S额外多出13天。此外，分配到100S处理的架子牛每公顷体重增加量更多（P≤0.001）。100S牧场上的架子牛在第28天的血尿素氮（BUN）浓度更高（P≤0.001），且略高于最大生长范围。100S和168N的每公顷春季总收入更高（P≤0.05），与100N相比，100S每公顷额外多收入82.38美元。100S的犊牛管理和饲料成本更高（P＜0.001），导致每公顷成本比100N增加514.60美元。100N和135N的净收益更高（P≤0.05），100N的净收益最大，由于饲料成本，其平均每公顷净收益比100S多361.00美元。由于替代效应，每公顷额外有525千克干物质（DM）的牧草可用，这表明100S牧场面积每增加2.81公顷就可以多放养一头架子牛，可能带来额外的经济效益。本研究结果表明，虽然补充DDGS在春季对架子牛和牧场性能有益，但在研究规模的生产系统范围内对整体经济效益并无益处。
