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RSPCA Australia knowledgebase

RSPCA Australia Knowledgebase

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What is mastitis in dairy cows?

Mastitis is an infection that causes inflammation of a cow’s udder. It is caused by bacteria or by injury, and the dairy industry believes it affects around 5-10% of dairy cows in the typical Australian dairy herd during their lactation. Mastitis is one of the most important health and welfare issues affecting dairy cows. The likelihood of a cow having mastitis is related to the shape of the udder and teats, as well as nutrition, hygiene and other procedures at milking. 

Mastitis causes a range of symptoms from unapparent (subclinical) to severe clinical disease. Clinical mastitis may become a serious animal welfare issue if the associated swelling and inflammation of the udder 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. If left untreated, severe clinical mastitis may cause the death of the cow. 

The RSPCA believes that good dairy management (e.g. good hygiene and careful handling at milking) will reduce the risk of mastitis and ensure that, when it does occur, it is detected early and treated promptly. The higher producing dairy cows tend to be at greater risk of mastitis, so only focusing genetic improvement on increased milk yield may increase the incidence of this disease. The Australian dairy industry recognises that mastitis is a major problem because it reduces the quality and amount of milk produced and has implemented initiatives to help prevent mastitis in the dairy herd (e.g. ‘Countdown 2020’ farmer extension and ‘Cups On Cups Off’ training for milking personnel).