A primary component of the project is to use a real time location system to study the indoor movement and social interactions of dairy cattle. We will investigate the possibility to select for increased milk yield considering effects of social interaction with the purpose to improve the social environment of the cows. The location and movement of the cows will also be used to investigate disease transmission. An existing simulation model of spread and control of mastitis causing pathogens will be further developed using cow location data and pathogen data. In the project, data are collected on two farms with around 200 cows on each farm. The position of every cow is recorded at 1 Hz.