Use of an experimental high-magnesium tall fescue to reduce grass tetany in cattle
Use of an experimental high-magnesium tall fescue to reduce grass tetany in cattle
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DOI：
10.2134/jpa1998.0491
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发表时间：
1998-10-01
期刊：
影响因子：
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通讯作者：
Mayland, HF
中科院分区：
文献类型：
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作者：
Crawford, RJ;Massie, MD;Mayland, HF
草疹(低镁血症)仍然是畜牧业的一个问题。高羊茅(Festuca arundinacea Shreb.)选择高镁含量的HiMag与其他4个品种进行比较，发现HiMag的镁含量比其他品种高22%，钙含量高18.5%，磷含量高9%，K水平与其他4个品种没有差异。无论品种，春季土壤钙、镁含量均低于秋季，而钾、磷含量高于秋季。[K/(Ca+Mg)]，HiMag比其他品种高(1.34比1.65)，春季比秋季高(1.91比1.31)。在牛(Bos Taurus)放牧试验中，1993年秋季放牧的奶牛血清镁含量高于1994年春季的8%，但在1994年春季没有差异。秋季放牧期间奶牛(无论是干犊还是哺乳犊)的血清镁含量没有差异，但在1995年春季产犊季节(HiMag为2.32 mg/dL比其他品种为2.07 mg/dL)接近显著(P=0.09)。除了1995年秋季在HiMag上与肯塔基-31号相比有差异(分别为58ib和43ib)外，所有品种的动物体重变化不受品种的影响，除1995年春季外，所有品种的正常饲料镁浓度(>；0.20%)和手足痉挛比率都在2.2以下，这可能解释了动物反应缺乏一致性的原因。在这些研究期间，在任何时候都没有观察到草手足癣的临床症状，然而，较高的镁浓度和较低的手足癣比率表明，在疾病风险较高的时期，HiMAg可以提供一种方法来降低牲畜的草手足癣发病率。
Grass tetany (hypomagnesemia) continues to be a problem for the livestock industry. An experimental cultivar of tall fescue (Festuca arundinacea Shreb.) selected for high Mg concentration, HiMag, was compared against four other cultivars for its ability to increase serum-Mg and reduce the risk of grass tetany, Forage from HiMag contained 22% more Mg, 18.5% more Ca, and 9% more P than other cultivars; K levels were not different. Regardless of cultivar, concentrations of Ca and Mg were lower while K and P were higher during the spring than the autumn. The tetany ratio [K/(Ca + Mg) on M-c basis] was tower for HiMag than for other cultivars (1.34 vs. 1.65); all cultivars had a higher ratio during spring than autumn (1.91 vs. 1.31). In cattle (Bos taurus) grazing trials, blood serum from steers grazing HiMag contained 8% more Mg in autumn 1993 but was not different in spring 1994, Blood serum Mg was not different for cows (either dry or nursing calves) during autumn grazing, but approached significance (P = 0.09) during the spring 1995 calving season (2.32 vs. 2.07 mg/dL for HiMag vs.other cultivars). Except for differences between calves on HiMag compared with Kentucky-31 in autumn 1995 (58 vs. 43 Ib, respectively), animal weight change was not affected by cultivar, Normal forage Mg concentrations (>0.20%) and tetany ratios below 2.2 for all cultivars in every season except spring 1995 may explain the lack of consistent animal response. No clinical symptoms of grass tetany were observed at any time during these studies, However, the higher Mg concentration and lower tetany ratio suggest that HiMag could provide a means of reducing the incidence of grass tetany in livestock during periods when risk of the disorder is high.