This thesis is to consider the reasons for Arcanobacterium pyogenes and why it causes an increase in mastitis on a dairy farm. In combination with other bacteria Arcanobacterium pyogenes can cause mastitis which leads to the destruction of tissues, otherwise known as pyogenes syndrome, it is generally considered a rare case of mastitis. In this thesis the goal is to find answers based on a single dairy farm’s problem with pyogenes syndrome. The aim is to identify the problem areas that contribute to the spread of the bacteria as well as to improve the livestock’s environment and make the conditions unfavorable for Arcanobacterium pyogenes.

The theoretical part is dealing with the most common incidences of mastitis as well as a more detailed look into pyogenes syndrome. The aim was to gather information on what causes the bacterium to thrive and to come up with an effective approach to relieve the cattle from mastitis. The practical part goes through circumstances of the farm, from where the problem was first noticed to what kinds of actions were taken against the mastitis.

The status of the udder health improved significantly after actions were taken. In the follow up period no new cases of pyogenes syndrome have been found. Other udder infections in the herd also decreased substantially. Focusing on prevention is the most important way to create a healthy environment for the dairy cow’s resistance to mastitis.