Calves Need Colostrum within First 6 Hours – Vet Guide 2025 🍼🐄

Hi there! I’m Dr Duncan Houston BVSc. As spring calving approaches, the critical importance of early colostrum intake cannot be overstated. New research shows that calves absorb 65 % of vital antibodies in the first 6 hours—and that gut closure drastically limits absorption after that. This guide dives into how to ensure your calves get colostrum early, the science behind passive immunity, practical feeding steps, and how Ask A Vet helps you manage colostrum protocols.

1. Why Early Colostrum Matters 🧬

• Passive immunity: Calves are born virtually immunodeficient and require antibodies from colostrum for protection.
• Absorption window: Calves absorb ~65 % of colostral antibodies in first 6 h, ~30 % by 12 h, and only ~10 % by 24 h.
• Gut closure: After ~24 h, intestinal lining changes prevent antibody absorption—even though colostrum is still valuable nutritionally.

2. Active vs Passive Immunity Explained

Active Immunity

Body-produced after exposure or vaccination—takes weeks to develop.

Passive Immunity

Delivered via colostrum; provides immediate protection critical in the neonatal period.

Calves rely entirely on passive immunity until their systems mature—make every early feed count! 🕒

3. Colostrum Timing & Quality Standards

To optimize transfer:

• First feeding: Aim within 2–4 h of birth; do not wait until calf nurses on its own.
• Volume: 10 % of birthweight (e.g., ~7 L for a 70‑kg calf) within 6 h, followed by another 5 % at 12 h.
• Quality: Use colostrometers or Brix refractometers—>22 % solids (~50 g IgG/L). If low, consider freeze‑dried supplements.

4. Feeding Steps & Techniques

1. Observe birth and act quickly—be ready with a nipple bottle or clean esophageal feeder.
2. If calf hasn’t nursed by 4 h, hand-feed or tube feed colostrum.
3. Warm feed to ~38–40°C; clean equipment to reduce pathogen introduction.
4. Repeat feed at 12 h and monitor for suckling behavior and vigor.
5. Note feeding time, volume, and quality in records for health tracking.

5. Signs of Failure of Passive Transfer (FPT)

• Weakness, poor suckle, lethargy
• Scouring or early onset illness
• High-risk calves (premature, twins, dystocia) especially need early colostrum.

6. What to Do in FPT Cases

• Administer a colostrum supplement or plasma transfusion.
• Work with Ask A Vet to determine intervention timing.
• Monitor calf health and consider delaying group integration.

7. Long-Term Benefits from Early Colostrum

• Lower scours, respiratory disease, mortality
• Better weight gain and feed efficiency
• Future reproductive health and productivity
• Reduced veterinary costs and improved herd performance

8. Ask A Vet: Your Support for Colostrum Protocols 📱

Ask A Vet offers expert assistance in:

• Creating script-based calving checklists with colostrum timings.
• Interpreting Brix or colostrometer readings.
• Tailoring feeding protocols for your calving system.
• Emergency helpline for struggling calves with FPT.
• Tracking herd protocol compliance and results over time.

9. Ensuring Smooth Colonization & Calf Health

1. After colostrum, provide clean bedding and a warm, dry environment.
2. Monitor passive transfer via blood tests or apparent calf health at 24–48 h.
3. Vaccinate dam as appropriate to boost colostral antibody content.
4. Follow up with starter feeds to support gut health and growth.

10. Key Take-Home Messages for 2025

• 65 % of antibody absorption happens within 6 hours. Delay costs lives.
• Feed quickly, feed quality colostrum, and track rigorously.
• Use supplements or plasma when needed.
• Ask A Vet helps implement and monitor colostrum protocols.

Conclusion

Colostrum isn’t just a first feed—it’s the foundation for a calf’s immune defense. Make it a management priority: feed early, feed quality, and feed deliberately. Partner with Ask A Vet to build precise colostrum workflows and track herd health outcomes. Here’s to a stronger, healthier calving season in 2025 and beyond! 🐄❤️