Mastitis in Dairy Cows: Early Signs and Prevention Checklist

Mastitis is inflammation of a cow’s mammary gland, often caused by infection. It matters for animal welfare as well as milk quality: affected animals may have a painful udder, abnormal milk and reduced production. Both obvious clinical mastitis and less visible subclinical infections deserve attention.

What are the early signs of mastitis?

• Milk containing flakes, clots or an unusual watery appearance.
• One udder quarter becoming hot, swollen, firm or sensitive.
• A sudden fall in milk yield from an individual cow.
• Reduced appetite, fever, lethargy or dehydration in more serious cases.

A cow with systemic illness, severe pain, rapidly worsening swelling or signs of dehydration should be examined promptly by a veterinarian. Do not assume all abnormal milk has the same cause; proper examination and, when appropriate, milk culture guide decisions.

Build a consistent milking routine

Healthy udders begin with careful everyday handling. Observe milk during forestripping so visible abnormalities are noticed early. Clean and pre-disinfect teats with a suitable dairy-approved product, allow the recommended contact time, and dry each teat with an individual clean towel before attaching the milking unit. Keep gloves clean, check equipment condition, and apply an appropriate post-milking teat disinfectant consistently.

Research-based advice from Cornell University’s Quality Milk Production Services emphasizes clean, dry teats, sound milking equipment and good housing hygiene. A stable routine matters more than complicated products used inconsistently.

Keep bedding clean and dry

Environmental mastitis organisms thrive where cows have frequent contact with mud, manure and wet bedding. Inspect stalls and resting spaces every day; remove wet material, clean heavily soiled lanes, and improve drainage around drinking points. The aim is to keep the udder and teat ends as clean as reasonably possible between milkings. Cornell’s environmental mastitis guidance highlights dry resting areas, clean alleys, good ventilation and appropriate preparation before milking.

Record cases instead of relying on memory

For every suspected case, record the animal ID, affected quarter, date, milk appearance, general condition, and veterinary assessment. Keep lab results and any prescribed treatment or milk-withdrawal details in the same record. Trends may reveal problems with one pen, milking unit or period of management. If cases are recurring, ask the herd veterinarian to review milking procedure, bedding, equipment, nutrition and milk testing together.

Simple daily mastitis-prevention checklist

• Observe every animal and forestrip before attaching the unit.
• Prepare teats using proper disinfectant contact time and single-use towels.
• Use clean gloves and maintain milking equipment.
• Post-dip every teat correctly.
• Check bedding, manure buildup and wet areas.
• Isolate or milk affected cows according to the veterinarian’s herd protocol.
• Keep clear records and respect medication withdrawal requirements.

Never start antibiotics or intramammary infusions without local veterinary direction. Mastitis can have different causes, and the right management depends on the animal and pathogen.

Sources and image credit

• Cornell University — DC305 pathogen codes and management
• Cornell University — Environmental mastitis
• Penn State Extension — Mastitis-causing pathogens

Featured photo: Cows in the shed, Kanimozhi Vennila / Wikimedia Commons (CC0)