Tiffany M E, McDowell L R, O'Connor G A, Martin F G, Wilkinson N S, Cardoso E C, Percival S S, Rabiansky P A
Department of Animal Science, University of Florida, Gainesville 32611-0910, USA.
J Anim Sci. 2000 May;78(5):1331-7. doi: 10.2527/2000.7851331x.
Angus x Hereford heifers (n = 50) were randomly assigned to bahiagrass pastures treated with biosolids varying in mineral content and evaluated for mineral status, with special attention to Cu. Biosolids and NH4NO3 were all applied at the rate of either 179 kg N/ha (X) or twice this (2X). Fertilizer was applied to .81-ha pastures for the following treatments: 1) Baltimore biosolids (1X = 179 kg N/ha); 2) Baltimore biosolids (2X = 358 kg N/ha); 3) Tampa biosolids (1X = 179 kg N/ha); 4) Tampa biosolids (2X = 358 kg N/ha); or 5) control NH4NO3 (1X = 179 kg N/ha) applied at two times. Pastures were divided into five blocks with each treatment represented once in each block. Copper loads varied from 8.8 to 42.2 kg/ha, and Mo loads varied from .27 to 1.11 kg/ha. Heifers (two per pasture) grazed their assigned pastures exclusively for 176 d. Liver biopsies were taken from all animals at d 1, 99, and 176, and blood samples on d 1, 50, 99, 135, and 176. Liver and plasma were analyzed for selected mineral contents, and blood was analyzed for hemoglobin and hematocrit. Experimental animals were generally low in mineral status when assigned to pastures and deficient in Se and P. By d 50, plasma Ca, Mg, Se, P, and Zn were adequate for all treatments. Plasma Cu declined (P < .03) for all treatments from d 50 to 176. Plasma Cu reflected depleted liver Cu storage, with the two Tampa and highest Baltimore treatment means lower in plasma Cu than the control at 176 d. Liver Fe concentrations were adequate for all treatments, and Mo concentrations (< 2.18 mg/kg) did not approach levels indicative of toxicity. Liver Cu declined (P < .05) with time for all treatments. By d 99, animals receiving the two Baltimore treatments and the lowest Tampa application rate had lower (P < .05) liver Cu than the control, and all treatments were lower at 176 d. The decline of animal Cu status (liver and plasma) reflects the low Cu status of bahiagrass and the possibility of high forage S (.30 to .47%) interfering with Cu metabolism. Forage Mo was low but was slightly higher in biosolids-treated pastures. High levels of biosolids applications to bahiagrass pastures were not detrimental to mineral status except Cu, which had a tendency to decline in plasma and for all biosolids treatments declined in liver.
将安格斯牛与赫里福德牛杂交的小母牛（n = 50）随机分配到用矿物质含量不同的生物固体处理过的巴哈雀稗牧场上，并对其矿物质状况进行评估，特别关注铜的情况。生物固体和硝酸铵均以179千克氮/公顷（X）或此用量的两倍（2X）的速率施用。肥料施用于0.81公顷的牧场，进行以下处理：1）巴尔的摩生物固体（1X = 179千克氮/公顷）；2）巴尔的摩生物固体（2X = 358千克氮/公顷）；3）坦帕生物固体（1X = 179千克氮/公顷）；4）坦帕生物固体（2X = 358千克氮/公顷）；或5）对照硝酸铵（1X = 179千克氮/公顷，分两次施用）。牧场被分成五个区组，每个处理在每个区组中各出现一次。铜负载量从8.8千克/公顷到42.2千克/公顷不等，钼负载量从0.27千克/公顷到1.11千克/公顷不等。小母牛（每个牧场两头）在其分配的牧场上单独放牧176天。在第1天、第99天和第176天从所有动物身上采集肝脏活检样本，并在第1天、第50天、第99天、第135天和第176天采集血样。分析肝脏和血浆中选定的矿物质含量，分析血液中的血红蛋白和血细胞比容。实验动物在分配到牧场时矿物质状况普遍较低，且缺乏硒和磷。到第50天，所有处理的血浆钙、镁、硒、磷和锌含量都充足。从第50天到第176天，所有处理的血浆铜含量均下降（P < .03）。血浆铜反映了肝脏铜储备的耗尽，在第176天，两种坦帕处理和巴尔的摩最高处理组的血浆铜含量低于对照组。所有处理的肝脏铁浓度都充足，钼浓度（< 2.18毫克/千克）未达到表明毒性的水平。所有处理的肝脏铜含量随时间下降（P < .05）。到第99天，接受两种巴尔的摩处理和坦帕最低施用量的动物肝脏铜含量低于对照组（P < .05），在第176天所有处理组的肝脏铜含量都更低。动物铜状况（肝脏和血浆）的下降反映了巴哈雀稗铜含量低以及高牧草硫含量（0.30%至0.47%）可能干扰铜代谢。牧草钼含量低，但在生物固体处理的牧场中略高。向巴哈雀稗牧场大量施用生物固体对矿物质状况（除铜外）无害，铜在血浆中有下降趋势，且在所有生物固体处理中肝脏铜含量都下降。
