What is mastitis?

Mastitis is inflammation of the mammary gland which produces milk, often called the udder, and nearly always caused by bacterial infections. It is important to remember the point that infection must get in through the teat canal before it infects the udder.

It cannot spread through the blood or across the barriers separating the quarters. Therefore to stop infection we have to prevent bacteria, contamination, and organic matter from coming in contact with the teat ends, where it can access the teat canal. Once in the teat canal the bacteria multiply and cause a mastitis infection which results in an inflamed udder. The cow will mount an immune response which results in white blood cells rushing into the quarter, resulting in high numbers of these somatic cells in the udder.

Broadly mastitis can be broken down into clinical (visible) and subclinical (invisible) forms

The signs of a clinical mastitis case are quite obvious although depending on the bacteria involved only some of the signs may be presented.

  • Swelling of the quarter
  • Abnormal looking clotted or clear looking milk
  • Foul smelling milk
  • Pain in the udder
  • Systemic sickness
  • Reduced milk yield

The harm that clinical mastitis can do is obvious. At best it will temporally result in loss of saleable or consumable milk and will need treatment. At worst the causative bacteria can spread from animal to animal resulting in further losses, and quarters and the animals themselves can be lost. 

For further information on Mastitis, prevention and treatment, download here.

Padraig Hyland is a large animal veterinary practitioner and Technical Advisory Vet with Bimeda,  a Leading Veterinary Pharmaceutical Company. He has some advice on Mastitis from a Vet's perspective. To read the interview, please click here