Causes of mastitis in dairy cows

Wet or manure-soiled bedding increases teat-end exposure, while contaminated hands, cloths, liners, or milk splash can transfer organisms during milking. Overmilking, poor unit alignment, unstable vacuum, rough removal, teat lesions, and a damaged teat end can weaken the barrier that normally protects the udder.

Environmental cases and milking-associated spread can coexist on the same dairy. A cluster after bedding changes points toward a different investigation from new cases appearing across the milking order. Freshly calved cows, animals with teat damage, and quarters with previous infection may need closer observation.

Clinical signs include altered milk and a swollen, warm, tender quarter. An animal may also lose appetite, appear depressed, or show fever. Subclinical mastitis is not visible at the udder and becomes apparent through milk-quality monitoring, individual-cow testing, or culture.

Identify the cow and affected quarter, divert her milk according to the farm protocol, and check her temperature, hydration, appetite, and ability to stand. If sampling is advised, obtain an uncontaminated sample before starting treatment. Keep it labelled and handled as the veterinarian or laboratory directs.

Trace likely entry points by examining teat ends, preparation routines, contact time for disinfectant, towel use, unit attachment and removal, liner condition, vacuum stability, holding-area cleanliness, stalls, and calving pens. Treatment decisions should follow the herd veterinarian's protocol, with medicine records and withdrawal periods applied precisely. Advice intended for dairy cows does not guide treatment of mastitis in people.

Request urgent veterinary help when a cow becomes recumbent, severely weak, dehydrated, unusually cold or feverish, stops drinking, breathes rapidly, or develops fast-progressing udder swelling or discolouration. Systemic illness can worsen quickly even when the first noticeable change was in the milk.

Call for review when multiple fresh cases emerge, an affected quarter fails to improve, the same cow relapses, or monitoring indicates a herd-level shift. Culture and pattern analysis can support targeted treatment and reveal whether housing, equipment, routines, or a contagious organism needs attention.

Ask which samples will be most informative, what supportive care the cow needs, how treatment response should be judged, and what findings justify a herd investigation. Clarify milk segregation, withdrawal dates, follow-up testing, milking order, equipment servicing, and prevention around calving and the dry period.