Animal welfare is an increasingly important subject gaining interest not only from veterinarians and scientists, but also from consumers. The public drive for higher welfare standards has increased the need for research to better understand the needs and nature of animals. Welfare assessment has typically focused on the elimination of negative welfare challenges (e.g. disease), whereas the recently established approach of Positive Animal Welfare (PAW) focuses on promoting positive experiences as an indicator of good welfare. Play behaviour is observed in the absence of environmental adversity, and as such reflects a good welfare state. Assessment of play behaviour can therefore provide veterinarians and livestock keepers an indicator of positive health, wellbeing and welfare. The introduction of motion sensor technology has allowed for detailed analysis of animal behaviours such as lying, playing, and feeding in a much less time-consuming manner. The impact of housing, socialisation, and play behaviour on future performance of dairy cattle has not been investigated. Therefore, this project aims to use accelerometers to investigate the impact of early life housing on calf play behaviour, and to assess the effect this may have on future health, performance and behaviour. The results will contribute evidence to the debate on calf housing systems and will aid veterinarians and animal health advisors when discussing housing and husbandry practices on farm.