About mastitis

What is the mastitis?

Mastitis is the inflammation of the mammary gland and udder tissue and is a major endemic disease of dairy cattle. It usually occurs as an immune response to the bacterial invasion of the teat canal by the variety of bacterial sources present on the farm, and can also occur as a result of chemical, mechanical, or thermal injury to the cow’s udder.


The main types are:

• contagious mastitis
• environmental mastitis

Contagious mastitis:

Contagious mastitis is the type of mastitis in chronic or subclinical mastitis.  It is sometimes referred to as Cow-to-Cow mastitis because it is generally spread from cow to cow. The gland is the primary habitat of bacteria causing contagious mastitis is on the udder and in teat lesions. These bacteria have poor survival in the environment when not associated with the skin or in the gland.


The major causes of contagious mastitis are Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp.

Sources of Infection and Transmission Methods

There are many sources of infection of this pathogen such as: shelter and fodder materials, equipment and air, bovine skin, other animals, the hands and nose of farm workers, insects, water supplies, even Skin of the nipple.

Its importance in the dairy areas lies because:

1) Causes acute or chronic mastitis.
2) Infections respond poorly to treatments, and
3) It is easily transmitted during milking

Environmental mastitis:

Environmental mastitis is mastitis that is derived from the environment in which the cow lives. The condition can be severe and prevention aimed at keeping the cow and her environment as clean and dry as possible is paramount

Causes and sources of infection

Environmental mastitis pathogens – present in the housing and bedding – can transfer during milking or between milkings, when the cow is loafing, eating or lying down. The pathogen can enter the teat canal by force during milking, for example, when liner slippage occurs. These environmental pathogens do not generally possess the same ability as contagious pathogens to adhere to and colonize the teat; dry cow therapy has little value in their control as these kinds of infections do not carry from one lactation to the next. High levels of environmental pathogens in a herd may cause normal SCCs but higher than average Bactoscan results.

Transition and post-calving cows are very susceptible to these infections because their natural defences are low. Large infections of environmental mastitis bacteria can contaminate teats, especially if udders are wet and exposed to mud and manure, such as when animals lie down during calving.