Protecting Your Calves From Pneumonia and Scours

As most of you all are aware, raising healthy calves is the cornerstone of a productive and profitable herd. Two of the most common and challenging health issues faced by young calves are pneumonia and scours (diarrhea). These diseases can result in significant economic losses and long-term impacts on calf development. As we turn the page into 2026 and winter has finally seemed to arrive, we are starting to see more scours and pneumonia in our herds, both in calves, but also some pneumonia in mature cows as well. In this newsletter, we’ll review some of the key information on pneumonia, some of which was covered in the last two newsletters to help you prevent, identify, and manage these conditions effectively.

CALF PNEUMONIA

What is it?

Calf pneumonia is a respiratory disease caused by a combination of bacterial, viral, and environmental factors. It commonly affects calves in the first 6 months of life and is one of the leading causes of mortality in young stock. It is important to note that a calf or older cow demonstrating just one of the symptoms below (eg just a cough), does not necessarily mean that animal has pneumonia, In many cases, we will look for two or more symptoms to determine of the calf or cow has pneumonia ( or bovine respiratory disease). UCDavis has a website and app to apply a score to symptoms to help determine a diagnosis or high likelihood of bovine respiratory disease (vmtrc.ucdavis.edu)

Symptoms:

• Coughing

• Rapid or labored breathing

• Nasal discharge          

• Fever (above 103.5°F or 39.7°C)

• Reduced feed intake and lethargy

Scientific Insights – Why it Matters?

Pneumonia accounts for up to 22% of pre-weaning mortality in calves (source: USDA). Pathogens involved include Mannheimia haemolytica, Pasteurella multocida,  Haemophilus somnus, and viruses like Bovine Respiratory Syncytial Virus (BRSV) and Infectious Bovine Rhinotracheitis (IBR), and Parainfluenza 3 Inflammatory responses in the lungs can lead to tissue damage and decreased lung capacity, which may impair growth and performance. Studies have shown lung consolidation in young calves (21-50 days of age) as seen by thoracic ultrasound of <1cm squared result in lower average daily gain (120g/day) and lung lesions 3 cm squared or greater seen at least once before 56 days of age resulted in 525 kg less milk in first lactation. Consolidation after weaning resulted in reduced reproductive performance and increased risk of removal from the herd. Some of these animals do not exhibit full blown symptoms of pneumonia and may not have even been treated.

Risk Factors:

• Poor ventilation in housing areas

• Sudden temperature changes or drafts         

• Stress from transportation or overcrowding

• Weakened immune system due to inadequate colostrum intake

Prevention Tips:

Colostrum Management: Ensure calves receive high-quality colostrum within the first 6 hours of life (minimum 50 grams of immunoglobulin G per L or a total of 200 gram IgG).

Housing: Provide well-ventilated and dry housing to reduce exposure to respiratory pathogens.

Vaccination: Use vaccines for respiratory pathogens such as BRSV, IBR, and Mannheimia haemolytica. Intranasal vaccines such as Inforce 3 and Nasalagen in newborn and preweaned calves, injectable vaccines such as Bovisheild, Express, Pyramid in calves 4-6 months of age or older

Minimize Stress: Handle calves gently and avoid overcrowding.

Treatment:

Antibiotic Therapy: Administer broad-spectrum antibiotics based on veterinary advice to combat bacterial infections. Examples include oxytetracycline (Oxyvet LA), Florfenicol (Nuflor, Resflor, Zeleris), or ceftiofur (Excenel, Cevaxel).

Anti-inflammatory Medication: Use NSAIDs (Flunazine, Metacam) to reduce inflammation and improve breathing. Many antibiotic combos such as Resflor and Zeleris include one of these NSAIDS.

Supportive Care: Provide adequate nutrition and hydration, including warm water or electrolyte solutions.

Monitoring: Regularly monitor temperature, breathing, and overall calf behavior to track recovery progress.

CALF SCOURS

What is it?

Scours, or diarrhea, is a common gastrointestinal disease in calves. It can result from infectious agents such as bacteria (e.g., Escherichia coli, Salmonella), viruses (e.g., rotavirus, coronavirus), or parasites (e.g., Cryptosporidium), as well as from nutritional issues.

Symptoms:

• Watery, foul-smelling diarrhea

• Dehydration (sunken eyes, dry nose)

• Weakness or inability to stand

• Loss of appetite

Scientific Insights:

• Calf scours is responsible for approximately 57% of calf mortality in the pre-weaning period (source: NAHMS).

• Cryptosporidium parvum and rotavirus are leading causes of scours in calves aged 1-3 weeks.

• Dehydration from scours can cause a loss of 8-10% of body weight in severe cases, leading to hypovolemic shock and death.

Risk Factors:

• Poor hygiene in calving pens and feeding equipment

• Insufficient or poor-quality colostrum           

• Abrupt changes in diet

• Contaminated water or milk replacer

Prevention Tips:

Colostrum Quality: Ensure calves receive adequate immunoglobulins through colostrum (target serum IgG levels ≥ 10 mg/mL in calves).

Clean Environment: Maintain sanitary conditions in calving and feeding areas.

Consistent Feeding: Provide a balanced and steady diet without abrupt changes.

Vaccination: Consider vaccinating dams against pathogens like rotavirus and coronavirus to pass immunity to calves. (Scourguard 4KC)

Treatment:

Rehydration Therapy: Provide oral electrolyte solutions to replace lost fluids and electrolytes. Administer small amounts frequently (e.g., 1-2 liters every 6-8 hours).

Intravenous Fluids: In severe cases, veterinary-administered IV fluids may be required to restore hydration and electrolyte balance.

Antimicrobial Treatment: Use antibiotics only when bacterial infections are confirmed. Common options include spectinomycin (LS Plus) or sulfa-based drugs (Trimidox, Borgal).

Nutritional Support: Continue feeding milk or milk replacer to ensure energy intake while treating dehydration.

Probiotics and Prebiotics: Use products to restore gut health and support recovery (Revive, Proflora calf boluses or powder).

MONITORING & RECORD KEEPING

Regular monitoring and record-keeping are essential to managing calf health effectively. Note symptoms, treatments, and recovery progress to identify patterns and refine your prevention strategies.