Mastitis in dairy cows: Causes and prevention

Mastitis is the most economically challenging disease on a dairy farm, with freshly-calved cows and heifers the most susceptible to mastitis, due to a weakened immune system after calving.

Also Read: Preventing mastitis in early lactation

A case of mastitis can cost €250-300 – mostly down to lost production.

Contagious Mastitis

Contagious mastitis is caused by bacteria such as Staph Aureus; Strep Uberis; and Strep. Agalactiae being transmitted between cows during milking.

Milk from one infected quarter can be spread to the teat skin of other quarters and other cows by milkers’ hands, liners and cross flow of milk between clusters.

Damaged teats / teat ends are particularly susceptible. Poorly maintained milking machines can also contribute to transmission of infection.

Also Read: Now’s the time to get the milking machine ready for the 2021 season

Prevention of contagious mastitis involves keeping teat / teat ends in good condition, disinfection of teats before and after milking, wearing clean gloves during milking, well maintained milking machines and good parlour procedures that keeps the cows calm.

Table source: Animal Health Ireland

Environmental Mastitis

Environmental mastitis is caused by bacteria such as E.coli and Strep Uberis, the primary sources being faeces and mud. The risk of infection from these bacteria increases when the environment is wet and dirty.

Areas where cows congregate such as water troughs, gateways, collecting yards and housing must be kept clean to minimise infection.

Most cases of environmental mastitis are seen in the period shortly before calving and up to a few weeks after calving, when a cow’s immune system is weakened. Prevention of environmental mastitis involves minimising levels of faeces and mud in the cow’s environment.

Table source: Animal Health Ireland