Grass Tetany in Beef Cows – Vet Guide 2025
In this article
Grass Tetany in Beef Cows – Vet Guide 2025 🐄
Welcome! I’m Dr Duncan Houston BVSc, here to guide you through grass tetany—a serious springtime risk for lactating beef cows grazing lush pastures. We'll explore causes, signs, forage testing, treatment, prevention, and how Ask A Vet can help you safeguard your herd.
1. What Is Grass Tetany? 🧬
Grass tetany, also called hypomagnesemia or "staggers," is a metabolic disorder caused by low blood magnesium in grazing cattle—especially nursing cows in early lactation. Magnesium is essential for nerve and muscle function, and when it drops too low, tremors, seizures, and sudden death can occur.
---2. Why It Happens in Spring
In spring, fast-growing forage has elevated potassium, which impairs magnesium absorption. Combined with lactation demands, cows rapidly deplete their Mg reserves, creating high tetany risk during long, wet spring grazing seasons.
---3. Clinical Signs to Watch For ⚠️
- Unusual behavior: nervous, excitable, may bump or attack handlers
- Muscle tremors & unsteady gait
- Difficulty standing or rising; in severe cases, collapse and seizures
- Rapid breathing & hyperthermia—a medical emergency
- Aggression after treatment: recovered cows may bolt from chutes—handle with caution!
4. Forage Testing & Interpretation 🧪
Evaluate pasture risk by testing forage for key minerals:
- Calcium, phosphorus, magnesium
- Potassium, sodium, sulfur
A K:(Ca+Mg) ratio >2.2 is high risk. Wheat, oat, and other fast-sprouting pastures often test high and should prompt magnesium supplementation.
---5. Treatment Protocol 💉
Immediate action is essential:
- IV infusion: administer calcium and magnesium salts—typically calcium-magnesium borogluconate
- Remove from pasture: move to dry paddock or stable
- Provide oral Mg supplement post-treatment to stabilize levels
- Observe closely: handle gently—minimize stress that can trigger seizures
6. Prevention Strategies 🛡️
- High-Mg mineral feed: provide 10–12% magnesium oxide, aiming for 3–4 oz per cow daily
- Timing: begin in late winter or early spring—continue through early lactation
- Pasture rotation: avoid lush, fast-growing paddocks; introduce legume-rich or dry forage
- Free-choice access: ensure mineral intake by making feeders readily available
- Monitor intake: watch consumption; intake below 2 oz/day increases risk
- Early signs tracking: monitor handlers and cows daily for tremors, excitability
7. Herd Management & Record-Keeping 📘
Maintain logs of:
- When mineral supplementation began and which products used
- Forage test results with dates and paddocks
- Incidents of tetany, treatments, and outcomes
- Weather conditions (rain, lush pasture growth periods)
Review data annually to refine prevention plans and tailor supplementation timing.
---8. Ask A Vet Support 📱
The Ask A Vet team is ready to assist you by:
- Helping interpret forage test results and mineral plans
- Guiding you through emergency IV treatment protocols
- Setting up pasture, supplement, and recordkeeping strategies
- Offering real-time support during lactation season management
9. 2025 Key Take-Home Messages
- Spring grazing risk: lush pastures high in potassium reduce Mg absorption
- Monitor early lactation cows: tremors or nervous behavior are warning signs
- Treat urgently: calcium-magnesium IV + pasture removal can save lives
- Supplement wisely: 3–4 oz/day of high-Mg mineral is essential
- Prep ahead: track forage, weather, and herd intake annually
- Ask A Vet helps ensure success with expert support and tailored herd plans
Conclusion
Grass tetany can strike suddenly and severely—but with proactive forage testing, consistent mineral supplementation, proper herd monitoring, and quick intervention, it is entirely preventable. Rely on Ask A Vet for personalized guidance, from emergency protocol to long-term herd health planning. Let’s keep your cows safe, productive, and thriving in spring 2025 and beyond! 🐮❤️
