Mastitis 

Causes of mastitis 

• Mastitis organisms - May be contagious or environmental

• Contagious bacteria - Spread from a cow with an infected udder to a healthy cow. Key  pathogenic bacteria include Streptococcus agalactiae, Staphylococcus aureus and Mycoplasma species. 

• Environmental bacteria - Come from the cow’s environment (bedding, soil, manure, etc.). 

• Summer mastitis - The spread of summer mastitis is usually linked to flying insects, specifically the head fly. Damaged teats are usually a perfect environment that flies are attracted to so the spread of pathogenic bacteria can occur here. 

Signs of mastitis 

Subclinical mastitis 

There are a number of types of tests (for example somatic cell count, Californian milk test) to detect if subclinical mastitis is present. More information about these tests can be found in our downloadable best practice guide on this page.

Clinical mastitis 

Clinical mastitis will be characterised in visible abnormalities in the udder, milk or the cow itself. 

Udder - May show swelling, heat, hardness, redness or pain

Milk - Consistency may be watery in appearance or may have visible flakes, clots or pus

Cow - Increase in body temperature, lack of appetite, sunken eyes and reduction in mobility

Treating mastitis 

If a mastitis case is chronic and management practices have not been successful in treating the infection, a vet should be called as soon as possible to treat the animal. 

Lactating cows 

Identify cases of clinical mastitis as quickly as possible as it will reduce the risk of spreading infection and make early treatment more effective. In consultation with your vet, it may  be appropriate to use a combination of sterile injectable antibiotics and teat sealant tubes.  

Non-sterodials (NSAIDs) have also been seen to be effective in the treatment of moderate and severe cases of mastitis.  

Dry Cow Therapy

The dry period is a critical time for cows to regenerate udder tissue. During this time, the udder will rid itself of many harmful pathogens which could potentially lead to 
a mastitis infection. However, the udder may still contract an infection during this period. Therefore, it's crucial to implement practices to prevent the contraction of any infections as well as eliminating any existing subclinical infections. 

1. Dry cow antibiotics 
Dry cow antibiotics aim to prevent new udder infections in the early dry period and can eliminate subclinical infections persisting from the previous lactation. Your local vet will prescribe an antibiotic based on the needs of your animal(s). 

2. Teat sealants 
Teat sealants can be used further to limit bacterial entry to the teat canal as they act as a physical barrier between the cow's udder and the environment. 

NoroSeal® Intramammary suspension is a teat sealant available from Norbrook. Learn more about NoroSeal here. 

Controlling mastitis 

There are two basic principles of mastitis control: (1) Elimination of existing infections and (2) prevention of new infections. 

Milk sampling 

Routine milk sampling and record keeping are essential for optimal herd management to reduce the levels of mastitis within a herd and subsequent productivity losses. There are several types of milk sampling tests including: 

1. Somatic cell counts 

2. Californian milk test 

3. Bactoscan counts 

4. Culture and sensitivity 

5. PCR testing 

Mastitis in the parlour 

Transmission of contagious and environmental pathogens to uninfected animals can occur at milking time. The following behaviours will help to prevent infections by pathogens:

1. Any dirty teats must be washed, dried and pre-dipped. 

2. All external surfaces of the milking clusters must be kept clean during milking. 

3. Milk removal should be as rapid as possible. 

4. Post-Milk Teat Disinfection (PMTD). Disinfectant is applied to the teat immediately after milking to kill organisms deposited there during milking. 

Environmental mastitis 

E. Coli is present in faeces and soiled bedding. The following will help in controlling environmental mastitis:    

1. Building ventilation and drainage 

2. Correct stocking density 

3. Frequent 'bedding up'

4. General hygiene 

5. Frequency and effectiveness of scrapping out of passage ways 

6. Reducing teat exposure to the disease 

7. Parlour routine 

Contagious mastitis 

Common mastitis organisms include Streptococcus agalactiae and Staphylococcus aureus.

Good parlour hygiene and good management practices will prevent contamination occurring and consequently, contagious mastitis spreading amongst the herd. 

Summer mastitis 

During the summer, it is recommended to use preventative methods, such as teat sealants and fly control products as part of drying off therapy.