Grass tetany in grazing milking cows.

Abstract

Statistical investigation showed that correlation existed between the incidence of grass tetany and the mean 24-hr, temperature, particulary in spring and autumn. There was also a significant positive correlation between the K/(Ca and Mg) ratio in the grass and the incidence of tetany. During the spring and autumn, when the average temperatures were below 14 degrees C., an increase in K uptake by the herbage being grazed was associated with a rise in temperature, and was followed, after a 5-day time-lag, by an increase in the number of cases of tetany, if the critical value of K/(Ca + Mg) (2.2) was exceeded. A fall in temperature was followed by a fall in the ratio value and in tetany incidence. High summer temperatures were associated with a lower value for the ratio and only a few cases of tetany occurred. The results favour the theory that the relationship between temperature and the incidence of tetany is correlated with the cationic composition of the herbage grazed. [See Abs. 1013.]-From authors'summary. (Abstract retrieved from CAB Abstracts by CABI’s permission)