Mastitis is an infectious disease of the udder, usually caused by a limited number of bacterial species. One such species is Staphylococcus aureus which causes approximately 25 to 40% of all mastitis cases and mastitis caused by S. aureus are also the most costly and difficult to treat.

In Sweden there are about 380,000 dairy cows. Of those, about 75,000 are treated each year with antibiotics for acute mastitis. The number of dairy cows varies greatly between countries. Denmark and the Netherlands have about 750,000 and 2.6 million cows, respectively.

Economical aspects of mastitis

In Sweden, the cost of each case of mastitis is estimated at more than 3,300 SEK due to reduced milk production, discarded milk and treatment costs. In the US, with more than nine million dairy cows the estimated annual cost is $ 50 per cow. Even a small increase in milk production and reduction of the number of mastitis cases have a great importance for the economy of this increasingly important part of the livestock. The demand for milk and milk products is steadily rising globally.