Drought followed by Grass Tetany.  Sound like a contradiction?  It can happen, especially when pastures were grazed heavily during a drought and /or during dormancy.  Spring growing conditions, combined with some moisture on relatively “denuded” pasture ground, means the only forage that’s available to grazing cattle is the lush fast growing new grass.     In ideal grazing conditions, there would normally be some old growth or residual forage that gets grazed along with new grass at turnout.  This helps dilute or minimize the amount of new grass being consumed; the new grass which poses the greatest risk to magnesium deficiency or Grass Tetany.

Magnesium deficiency can occur in many areas and many factors complicate it based on growing conditions, soil types and fertility, grass types and prior management of the land.  As listed above, pastures grazed heavily the prior season and used again coming out of a drought or in improving moisture conditions, further aggravate the risk.   Delaying turnout to drought stressed pasture is strongly recommended as to help pastures recover from previous heavy grazing and it can also help reduce the risk of grass tetany.  However, sometimes producers have limited options or limited feed resources.

Grass tetany can affect all ages and types of cattle, but is most likely observed in mature lactating beef cows due to a high magnesium requirement for milk production (nearly three times greater than in early gestation).   Older, heavier milking cows are the most severely affected.  Magnesium is not readily available from body stores so it must be provided in the diet daily.  Therefore a good supplemental program is a necessity when forage and growing conditions pose a risk. 

Forages and other feedstuffs will provide some magnesium but supplementation should be practiced during high risk and high demand periods.  This sounds simple, but most feed grade sources of magnesium, such as magnesium oxide, are unpalatable. Providing proper levels of magnesium can be a real challenge. That is why it is of vital importance to find a highly palatable supplement with consistent daily intake that you can count on to deliver essential magnesium.  CRYSTALYX^® Brand Supplements have options that can do this.

CRYSTALYX^® products fortified with additional magnesium include:  Super Mag™, Hi-Mag Fescue-lyx^®, and Breed UP^® 17 Mag.  These contain 4.0% or more magnesium and would supply about 15 to 20 grams of magnesium at ¾ to 1 pound of intake per head per day, to aid in the prevention of grass tetany during conditions of high risk.   Other more regional based formulations also exist and work very well.

Grass tetany can be very costly once symptoms appear since mortality of cows can be very high resulting in orphaned calves.  Preventive measures such as feeding the CRYSTALYX^® products listed above are practical, cost effective, and easy to implement.   It’s often advised to begin supplementing magnesium 2 to 3 weeks prior to known risk periods. Make sure your magnesium delivery is palatable and in front of your herd every hour of the day with CRYSTALYX^® Brand Supplements.