What is mastitis in dairy cows?

Mastitis ranges in severity from hidden illness with no clinical signs (subclinical), to mild or severe visibly apparent disease (clinical mastitis). Clinical mastitis is a serious animal welfare issue as the swelling and inflammation of the udder that comes with the disease is very painful. Affected cows may show clear signs of discomfort, including abnormal posture (hunched), increased sensitivity of the udder and teats to touch, rapid breathing and heart rate, and a high temperature.

Unfortunately, mastitis is not always easy to detect in its early stages, particularly when the redness and swelling of the udder is not obvious. Routine and suspicion-based testing of individual or grouped milk is used to detect mastitis early [1]. Prevention of mastitis through good management is preferable to widespread treatments. For cows who contract clinical mastitis, treatment with anti-inflammatory medications reduces pain and inflammation, and some cows will also need treatment with appropriately selected antimicrobials [2,3]. If left untreated, severe clinical mastitis can cause the death of the cow in some cases. Mastitis is also a major problem economically for dairy farmers because it reduces both the quality and amount of milk produced.

Good dairy management, including a clean environment, excellent milking hygiene, well-trained farm staff, and sound milking and testing protocols will reduce the risk of mastitis and ensure that, when it does occur, it is detected early and treated promptly. The Australian dairy industry has implemented initiatives to help prevent, detect and treat mastitis in the dairy herd, such as the Countdown udder health information resources, and the Milking and Mastitis Management training program for milking personnel. Cows with high milk production tend to be at greater risk of mastitis [4], so selectively breeding for increased milk production is not recommended without also prioritising other health and welfare traits.