Thompson J K, Reid R L
J Anim Sci. 1981 May;52(5):969-76. doi: 10.2527/jas1981.525969x.
The utilization of minerals in orchardgrass (Dactylis glomerata L.) fertilized with kieserite (2,240 kg/ha) was examined in spring with lactating beef cows and wether lambs. Kieserite increased the concentration of Mg in vegetative herbage from .22 to .29% ( P less than .01) and of S from .20 to .29% (P less than .01), with little effect on other minerals. Fertilization also increased (P less than .01) apparent absorptions of Mg and S by lambs fed cut orchardgrass, from 24.5 to 36.5% and from 58.6 to 66.9%, respectively, and increased (P less than .01) apparent Mg retention from +.16 to +.33 g/day. Fertilization did not affect dry matter digestibility or apparent absorption of N, Ca or P by lambs. composition of blood and saliva of beef cows grazing fertilized and unfertilized pastures was determined during a 2-week period in early spring. Cows grazing kieserite-treated pastures showed a small increase (P greater than .05) in serum Mg, ultrafiltrable Mg and red blood cell (RBC) Mg, and fewer cows on the fertilized pastures showed severe hypomagnesemia (less than 1.0 mg/100 ml) after the first day of grazing. The decline in blood Mg concentrations was not accompanied by hypocalcemia or by changes in serum Na or K concentrations, but serum inorganic P decreased (P less than .01) markedly during the first 10 days of grazing. Ultrafiltrable Ca in blood was affected by fertilizer and period, but it is questionable whether either ultrafiltrable Mg or Ca would provide a more sensitive index of mineral status than serum concentrations. Concentrations of K, NA and P in saliva were more susceptible to fertilizer and period effects than were concentrations in blood, although all values fell within a normal range. There was no evidence of an inverse relationship between serum Mg and concentration of K in saliva of cows after a change from a winter-type diet to spring herbage containing high levels of N and K.
在春季，用基性硫酸镁（2240千克/公顷）对果园草（鸭茅）施肥后，研究了泌乳期肉牛和羯羊对其中矿物质的利用情况。基性硫酸镁使营养期牧草中的镁浓度从0.22%提高到0.29%（P小于0.01），硫浓度从0.20%提高到0.29%（P小于0.01），对其他矿物质影响较小。施肥还使（P小于0.01）采食割下的果园草的羔羊对镁和硫的表观吸收率分别从24.5%提高到36.5%和从58.6%提高到66.9%，并使（P小于0.01）镁的表观保留量从+0.16克/天提高到+0.33克/天。施肥对羔羊的干物质消化率或对氮、钙或磷的表观吸收率没有影响。在早春的两周时间里，测定了在施肥和未施肥牧场放牧的肉牛的血液和唾液成分。在基性硫酸镁处理过的牧场放牧的母牛血清镁、超滤镁和红细胞（RBC）镁略有增加（P大于0.05），施肥牧场中出现严重低镁血症（低于1.0毫克/100毫升）的母牛数量较少。放牧第一天后，血液镁浓度下降，但未伴有低钙血症，血清钠或钾浓度也未发生变化，但在放牧的前10天血清无机磷显著下降（P小于0.01）。血液中的超滤钙受肥料和时期的影响，但超滤镁或钙是否能比血清浓度提供更敏感的矿物质状况指标尚值得怀疑。唾液中钾、钠和磷的浓度比血液中的浓度更容易受肥料和时期的影响，尽管所有值都在正常范围内。从冬季型日粮改为含高氮和高钾的春季牧草后，没有证据表明母牛血清镁与唾液中钾浓度之间存在反比关系。
