Vet 2025 Guide: Bovine Summer Pneumonia by Dr Duncan Houston 🌾

As summer heat rises, so does the risk of bovine summer (or “pasture”) pneumonia in young calves turned onto grass late in the season. In this 2025 vet guide, Dr Duncan Houston explains causes, detection, and treatment protocols to protect herd health, prevent losses, and maintain calf performance through summer months. ☀️🐄

1. What Is Bovine Summer Pneumonia?

Pasture pneumonia is a respiratory disease primarily seen in pre‑weaned to weaned calves soon after grass turnout in warm months. Kansas State Diagnostic Lab vets identify two major viral triggers:

• Bovine respiratory syncytial virus (BRSV)
• Bovine coronavirus

These viruses damage the lungs, enabling secondary bacterial infections that cause severe bronchointerstitial pneumonia and high fevers (>106 °F)."

2. Real Case Overview: Kansas Study

A commercial beef herd of 200 spring-calving cows experienced an outbreak roughly three weeks post-turnout:

• All calves were vaccinated for respiratory and clostridial pathogens at day 3 and boosted at ~4 months.
• Three weeks after pasture turnout in May, multiple calves began showing high fevers, labored breathing, and open-mouth panting.
• Local vet necropsied fatalities, confirming bronchointerstitial pneumonia and BRSV on PCR; secondary bacteria isolated.
• Sixty calves fell ill; seventeen died before treatment could begin.
• Remaining sick calves received appropriate antibiotics and supportive care, reducing further losses.

Lesson? Even well-vaccinated herds can suffer outbreaks—prompt vet involvement is crucial.

3. Why It Hits After Turnout

Several factors converge post-turnout:

• Exposure to new viruses (BRSV, bovine coronavirus).
• Environmental stress: temperature swings, weather, grouping dynamics.
• Lung tissue damage by viruses, followed by opportunistic bacterial infection.

4. Spotting Signs Early

Key indicators include:

• Temperatures ≥ 106 °F — far above the normal calf range of 101–103 °F.
• Labored or open-mouth breathing and increased respiratory rate.
• Variable coughing, nasal discharge, and lethargy.

Time is critical. Rapid recognition and vet assessment are essential for treatment success.

5. Diagnosis & Testing Procedures

What the veterinarian needs:

• Necropsy & lung tissue from early deaths to confirm pneumonia type.
• PCR testing for BRSV and coronavirus.
• Bacterial culture to identify secondary pathogens and antibiotic sensitivity.

This information tailors antibiotic therapy and verifies the viral triggers—avoiding guesswork and delays.

6. Treatment Plan

Dr Houston’s recommendations:

1. Administer broad-spectrum antibiotics targeted to cultured pathogens.
2. Provide supportive care: anti-inflammatories (NSAIDs), soft feeds, and clean water.
3. Isolate sick calves to reduce viral spread.
4. Maintain optimal airflow in shelters to reduce humidity buildup.

Treatment must begin immediately—delays of even 24 hours can increase mortality.

7. Vaccine Strategy & Timing

Vaccination should protect calves before virus exposure. Dr Houston outlines best practice:

• Initial respiratory vaccine at ~3 days old (respiratory + clostridial disease).
• Revaccination ~2–3 weeks before pasture turnout (around 4–5 months).
• Ensure proper handling and compliance per label instructions.

Even with correct timing, outbreaks can occur due to changing virus strains or environmental stress, so always be vigilant.

8. Herd Management & Biosecurity

Effective tactics to reduce summer pneumonia risk include:

• Quarantine incoming calves to prevent pathogen introduction.
• Minimize crowding during critical post-turnout weeks.
• Provide shelter from rain, wind, and temperature extremes.
• Monitor temperature trends among recently turned-out calves—fever clusters suggest outbreak.

9. Economic Impacts & Herd Performance

Calf morbidity and mortality can't be measured only in deaths—morbid calves underperform at weaning and beyond:

• Pneumonic calves may weigh significantly less at weaning.
• Heifers affected early may reach puberty later and produce less milk.
• Costs rise due to vet bills, antibiotics, and reduced overall productivity.

Preventing summer pneumonia promotes calf health, growth, and long-term herd value.

10. Follow-Up & Monitoring

Post-outbreak, Dr Houston recommends:

• Weekly monitoring of calf temperatures and respiratory signs.
• Review of vaccination and turnout protocols.
• Record keeping: number treated, response time, survival.
• Lab analysis where possible to refine antibiotic choices in future outbreaks.

11. Integrating into 2025 Beef Health Plans

This guide is part of a modern herd health strategy alongside:

• BRD protocols in calves and feedlot cattle.
• Fly and pest control to reduce insect stressors.
• Nutrition and deworming to shore up immunity during pasture change.

12. Future Directions & Emerging Tools

Dr Houston highlights innovations:

• On-farm PCR testing to get rapid pathogen ID.
• Portable ultrasound to detect early lung changes.
• Wearable sensors for continuous temperature and activity monitoring.

13. Recap: Best Practice Checklist ✔️

1. Plan vaccines for early life and ~2–3 weeks pre-turnout
2. Turn out calves in small groups to monitor health
3. Monitor daily for fever, respiratory distress
4. Call vet at first signs—blood work, necropsy, PCR
5. Implement targeted antibiotics + supportive care
6. Isolate and manage affected calves; sanitize pens
7. Record outcomes; refine plan for next season

By following Dr Houston’s summer pneumonia protocol, producers can significantly reduce sickness and loss during critical post‑turnout months—protecting calf growth, survival, and farm income. 🌿🐂