Farm Store | articles | The Science of Spring Tetany

The Science of Spring Tetany

Identifying And Managing Tetany

Green grass is a welcome sign of spring, longer days and warm temperatures ahead. While it may be tempting to let your cattle loose on your lush green pastures, take care to ensure you’re reducing your herd’s risk of grass tetany incidents. Grass tetany most frequently occurs when grass is growing rapidly following a cool period (45-60°F). This early grass growth may be high in potassium and low in magnesium. Excess potassium may result in tetany as it can interfere with magnesium absorption in cattle.

Prevention is key when it comes to grass tetany, as it’s easier to prevent than treat. Unfortunately many times the first sign of a problem with grass tetany is finding dead cows in your pasture. However if you notice cows staggering, involuntary muscle contractions, convulsions, frothing at the mouth, separation from the herd and vocalization, these may be signs your herd has a tetany incident.

cows grazing in a field

By following the tips below you can help prevent tetany in your herd:

  • Implement Grazing Management – Resist the temptation to let your cattle graze on new grass. Cattle shouldn’t graze the pasture until the new grass is 4 to 6 inches tall, as immature plants have less available magnesium.
  • Add Legumes to Pasture – When planning your next seeding, consider using a pasture blend that contains 30% legumes. Legumes like clover and alfalfa have high magnesium levels and will compensate for the magnesium shortage often found in new grass growth.
  • Provide Magnesium Supplementation – “The key to preventing tetany is starting early enough to get intake up on a ‘high-mag’ mineral, at least 30 days prior to the anticipation of issues,” explains Mike Peacock, Southern States Livestock Feed Sales Manager. Any cows that will be calving within 30 days should already be getting extra magnesium supplementation via their pre calving mineral. Southern States has Mag-O-Min and other High Mag Mineral products to aid in preventing tetany.
  • Ensure Magnesium Availability - High Mag minerals must be available to your herd 24/7 during tetany season. Even one day without mineral availability can put your herd at risk. Likewise, locate mineral feeders where they will get optimum consumption by the herd. You don’t want the herd to over or under consume the magnesium mineral.
  • Identify High Risk Pastures – If you’ve had episodes of tetany in specific pastures in the past, use these areas to graze less susceptible animals. Generally speaking, heifers, dry cows or cows with calves over 4 months old, and stocker cattle are less likely to develop tetany and can graze higher risk pastures.

If you have any question about managing Spring Tetany in your herd - contact your local Southern States specialist.

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