|High levels of potassium will interfere with magnesium absorption by the animal. Therefore pastures fertilized with products such as potash, chicken litter, and ammonium sulfate will only increase the chance of grass
Grass tetney generally occurs in cows shortly after giving birth during times of the year when tetney is most likely to occur. Late winter until early spring when cattle are grazing lush forages is the time grass tetney will most likely occur. At the onset of tetney, animals will appear nervous, and muscles can be seen twitching. As the condition progresses, animals will have problems walking, will eventually go down, and will normally lie on one side and thrash about. If the condition is not corrected, death may occur within 3 hours.
Since nothing can be done to control the weather, the best alternative to prevent grass tetney is to feed a complete mineral with adequate levels of magnesium. Most high magnesium minerals will contain 14% magnesium for grass tetney prevention. Magnesium is very unpalatable, so you should only provide high magnesium minerals to cows from 30
days prior to and through grass tetney season. During the other times of
the year, you should provide a complete mineral that contains at least 3% magnesium, along with at least 6 % phosphorous.
If you have an acute case of grass tetney, a sterile solution containing magnesium and calcium is given intravenously to the cow. This must be done slowly to prevent rapid increases in blood calcium levels which can cause heart failure.
The best way to stop grass tetney is to prevent it. To accomplish this, provide a high magnesium mineral to cattle beginning in early January. Make sure that the mineral is provided to cattle at all times and that they are consuming an average of 3 ounces of mineral per head per day. If you have any questions concerning grass tetney or other mineral concerns, please contact your local Cooperative or e-mail me at