Grass tetany in grazing milking cows.
Grass tetany in grazing milking cows.
复制标题
放牧奶牛的草抽搐。
DOI：
10.18174/njas.v5i1.17745
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发表时间：
1957
期刊：
影响因子：
--
通讯作者：
M. Hart
中科院分区：
文献类型：
--
作者：
A. Kemp;M. Hart
1 .统计调查显示，草地抽搐的发生率与24小时平均气温之间存在显著的相关关系（图1、2）。在出现频率上，可以区分出两种类型的波动，一种是与全年平均温度相关的季节性波动，另一种是与温度日变化相关的若干短暂波动。春季和秋季气温低于14°c时，出现“草癣期”，存在季节性波动。在较温暖的夏季，几乎没有草癣病例。在这些草地上的短暂波动与低于大约14°C的温度波动密切相关。在温度从低于14°C的水平上升后约5天，破伤风病例数增加，而在温度下降后平均5天，破伤风病例数下降。因此，在短暂的波动中，在作用（温度变化）和反应（手足颤病例数）之间存在5天的时滞，我们将这一时滞与温度引起的牧场矿物成分的变化联系起来。2 .对采自牧场的大量草样进行化学检查，发现有和没有手足搐病的病例_比草Mg手足搐病时，1908年头期（即低于14°C水平）手足搐病很少。这增加了比值的值，因为Ca和Mg的摄入量实际上保持Ca + Mg不变。当温度下降时，位置就颠倒了。春季和秋季持续低温比夏季持续高温产生更高的~ Ca + Mg比值值。这些结果支持这样一种理论，即温度和破伤风发病率之间的关系与动物摄入的牧草的阳离子组成有关。
1 Statistical investigation showed that a significant correlation exists between the incidence of grass tetany and the mean 24-hour temperature (Figs. 1 and 2). Two types of fluctuations may be distinguished in the frequency of tetany, viz. a seasonal fluctuation which shows a correlation with the mean temperature during the year, and superimposed on this a number of brief fluctuations showing a correlation with the daily changes in temperature. The seasonal fluctuation is seen in the occurrence of the "grass tetany period" in spring and autumn when the temperature level is below about 14° C. During the warmer summer months there are practically no tetany cases. The brief fluctuations during these grass tetany periods are very closely correlated to the temperature fluctuations below the level of ap proximately 14° C. About 5 days after a rise in temperature from a level below 14° C there is an increase in the number of tetany cases, whereas on an average of 5 days after a fall in temperature there is a fall in the number of cases. Thus during the brief fluctuations a time-lag of 5 days is to be noted between action (change in temperature) and reaction (number of tetany cases), and we associated this time-lag with a change in the mineral composition of the pasture brought about by the temperature. 2 Chemical examination of a large number of grass samples taken from pastures with and without tetany cases that _ ratio grass Mg tetany When few tetany 1908 head period (i.e. below the 14° C level). This increases the value of the _ ,, ratio, as the Ca and Mg intakes remain practically Ca + Mg constant. When the temperature falls the position is reversed. Consistently low temperatures in the spring and autumn produce a higher ~ Ca + Mg ratio value than consistently high temperatures during summer. 4 These results favour the theory that the relationship between temperature and the incidence of tetany is correlated to the cationic composition of the herbage ingested by the animals.