Winning the battle against mastitis

Contagious mastitis is caused by bacteria such as Staph. aureus and Strep. agalactiae that are transmitted between cows during milking. Occasionally Strep. uberis and Strep. dysgalactiae (normally classified as environmental pathogens) can also be transmitted between cows during milking.

Environmental mastitis is caused by bacteria such as Strep. uberis and E. coli. The primary source is faeces and mud, so wet and dirty conditions are a risk for this type of mastitis.

Prevention of environmental mastitis involves minimising build-up of mud and manure in the cow’s environment to keep udders and teats clean and healthy. This applies especially to areas with high cow traffic, such as water troughs, gateways, collecting yards, feed pads and housing systems.

Subclinical mastitis during lactation can also be caused by bacteria known as the minor pathogens such as CNS and C. bovis.. These bacteria usually cause subclinical mastitis and contribute to a cow’s rise in SCC towards the end of the lactation. They are often found on the skin of the cow so prevention is through good teat disinfection after milking.

Use good milking technique and a consistent routine.

Contagious mastitis is caused by bacteria such as Staph. aureus and Strep. agalactiae that are transmitted between cows during milking. Occasionally Strep. uberis and Strep. dysgalactiae (normally classified as environmental bacteria) can also be transmitted between cows during milking.

Milk from one infected quarter is spread to the teat skin of other quarters and cows by dirty hands or gloves, by teat cup liners and cross flow of milk between teat cups.

Damaged teat ends are particularly susceptible to infection. Malfunction or poor use of the milking machine can contribute to transmission of infection.

Prevention of contagious mastitis involves:

- disinfection of teat skin after milking

- keeping hands and gloves clean during milking

- careful use of machines that are operating well

keeping cows settled and teat ends healthy.

Ensure that cows enter the farm dairy willingly by maintaining good stockmanship.

Calm cows dung less frequently, kick the cups off less often, have a better milk let-down and move through the dairy more easily than stressed and anxious cows.

Cows that are fearful produce adrenalin that prevents milk let-down. Minimise fearful experiences in the dairy such as yelling, use of sticks, dogs or electrified backing gates.

Foremilk strip cows to detect abnormal milk.

Foremilk stripping, or fore-stripping, is the single most effective way to detect clinical mastitis. Consider fore-stripping all cows in their first month of lactation and in periods of high risk.

Periods of high risk include the calving period, or when the clinical case rate is too high, or when the bulk milk SCC is too high.

Routine fore-stripping of cows in the first month of their lactation also helps accustom them to having their teats touched and provides an effective signal for milk let-down.

If done poorly, however, fore-stripping can contribute to the spread of bacteria from teat to teat via milkers’ hands. Good milkers rinse and disinfect their gloves if they get milk on them.

SmartSAMM strongly recommends fore-stripping all cows in the colostrum mob at least once a day.

Farmers should consider systems to allow regular fore-stripping of all cows in their first month of lactation, or all lactation.

Fore-strip all cows when clots are found on the filter sock and/or the bulk milk SCC shows a sudden increase.

Use post milking teat disinfection on every teat after every milking.

Bacteria in milk from infected quarters may contaminate the skin of many other teats during milking. For example, after a liner has milked an infected quarter, bacteria may be transferred to the next five-six cows milked with that cup.

After milking, bacteria multiply on the teat skin and may extend into the teat canal. If the whole surface of each teat is disinfected immediately after milking, this spread can be minimised. Teat disinfection also helps to keep teat skin supple and healthy.

Teat disinfection after milking reduces new infections due to cow-associated bacteria such as Staph. aureus by 50% and is also important in reducing Strep. uberis infections. It is one of the most effective cell count and mastitis control measures available, but it only works if it is done thoroughly.

Teat disinfectants must be diluted to the correct concentration for use. The active ingredients often lose their disinfectant ability over time after mixing, and if you include additives to improve skin condition (emollients) these may reduce disinfectant activity. Any contamination with milk and other organic material also reduces activity. Correct mixing each day is best to get maximum performance.

Some emollients are not suitable for use with particular disinfectants.

Failure to cover the whole teat of every cow at every milking and poorly diluted teat sprays are the most common errors in teat disinfection.