Oh boy – it is Grass Tetany Season.
If you don’t make it to the end of this post – here’s the net-net: Get Magnesium in your fields. Now. Then end.
I am here to tell you, who knew that grass could make a cow sick?
Are you kidding me?
Eating grass can make a cow sick?
Cows are supposed to eat grass!
All a cow eats is grass.
How on earth can grass make a cow sick?
These, my friends, are great questions.
Yes, eating grass can make a cow sick.
Stupid, but true.
How can grass make a cow sick?
When a cow has been on dry hay all winter, and is thrown onto a lush, green, grassy pasture in spring – it is a recipe for disaster.
By disaster, I mean, Grass Tetany.
Here’s the problem.
- Hay is dry.
- (good) Hay has normal amounts of potassium and magnesium in it.
- Fresh, Lush, New, Green grass does not have normal amounts of potassium and magnesium in it.
- Fresh, Lush, New, Green grass has too much potassium and not enough magnesium in it.
- Green grass, first thing in the morning, on an empty stomach is dangerous territory.
Don’t ask me.
The basic underlying problem is a lack of magnesium. Really, it’s the high potassium levels in the fresh, rapidly growing grass that is the culprit. Potassium displaces magnesium. This means that even if your grass has magnesium in it, because fresh grass is so crazy high in potassium – your cow can’t get enough of the magnesium from the grass because the potassium is kicking the magnesium’s butt.
Signs Your Cow Could have Grass Tetany
“Symptoms of tetany include cows staggering, excitability, involuntary muscle contractions, convulsions, frothing at the mouth, and vocalization. Tetany can strike quickly, leaving the animal dead within hours of the onset of symptoms, making detection and treatment that much more difficult. In the battle against grass tetany it’s best to try to prevent it rather than treat it.”
-Southern States (source)
Preventing Grass Tetany couldn’t be easier – Magnesium.
There are several steps you can take to minimize your chances of ever having to deal with Grass Tetany:
Provide Magnesium Supplements
Help to offset any magnesium deficiencies by providing magnesium minerals. Be sure the minerals are available 24/7 during tetany season. Many folks put out “high-Mag Blocks” this time of year. Magnesium loose minerals are even better. Because Magnesium isn’t very palatable (this is what I’m told by the feed store people) it’s important to use a high quality Magnesium supplement so the cows will eat it. To see the minerals we use go here.
Be sure to Provide Enough
Make sure you have enough magnesium for your herd. You don’t want the minerals to run out. If the cows empty the bin it wont take long for a problem to start.
Keep Feeding Dry Hay
Even when your pasture is growing so fast the cows can’t eat it all, you still should offer some hay. You will know when they don’t need the hay any longer, because the cows will stop eating it.
Pastures that contain a variety of grasses (and even some legumes) can decrease the chances of Grass Tetany. When you seed your pasture, consider adding some clover or alphafa into the field.
Time it Right
In order to minimize problems, don’t turn your cows onto a fresh green pasture first thing in the morning. It is best to move cattle onto new ground late morning or afternoon when the dew is gone.
Grass Tetany is not hard to prevent – just be sure you have plenty of good, quality magnesium available to your herd 24/7.