Preventing Grass Tetany - Key Tips for Cattle Health

By Blake Jackson

Grass tetany, a metabolic disorder in cattle, can cause sudden collapse and even death, especially in early spring. This potentially devastating condition is linked to magnesium deficiency and is often seen in cows grazing lush, cool-season grasses.

"If you’ve ever seen a cow suddenly collapse in early spring, seemingly out of nowhere, you might have witnessed a case of grass tetany," says Eric Bailey, University of Missouri Extension state beef nutritionist.

Grass tetany, also known as grass staggers, occurs when blood magnesium levels drop too low. While these pastures are rich in energy and protein, they often lack sufficient magnesium and contain excessive potassium, which hinders magnesium absorption.

"Understanding the causes, symptoms and prevention strategies for grass tetany can help cattle producers avoid costly losses," says Harley Naumann, MU Extension state forage specialist.

Symptoms of grass tetany include increased excitability, teeth grinding, excessive salivation, muscle spasms, and loss of body control. In severe cases, collapse and death can occur rapidly.

Traditional solutions have focused on magnesium supplementation, but these methods are not always effective due to palatability issues and the complex interplay of other minerals.

Recent research highlights the importance of potassium and sodium in magnesium absorption. High potassium levels in pastures can block magnesium absorption, while low sodium levels can hinder its transportation.

"Providing free-choice salt or increasing the amount of salt in your free-choice mineral can support magnesium absorption and be a cost-effective strategy for reducing the risk of grass tetany," says Bailey.

Additionally, studies show that adequate soil phosphorus levels can improve magnesium availability in forages.

Effective prevention strategies include:

• Providing high-magnesium supplements, especially during early spring.
• Increasing salt consumption through mineral supplements or direct salt supplementation.
• Limiting excessive potassium fertilization in pastures.
• Grazing mixed pastures with legumes to balance mineral content.

By understanding the complex factors contributing to grass tetany and implementing preventive measures, cattle producers can protect their herds and minimize losses from this potentially devastating condition.

Photo Credit: gettyimages-r-j-seymour