The dairy-beef sector has increased markedly in the UK due to the use of sexed dairy semen as not all cows within the dairy herd will be needed to breed replacement dairy heifer calves. The majority of these dairy-bred calves will enter the dairy-beef production cycle by being sold onto calf rearing units at a young age. At such rearing units, these calves will enter an unfamiliar environment and potentially be mixed with other calves from other farms. These all present a challenge to such calves. The initial objectives of this study were to:

• assess the respiratory health of dairy-beef calves, sourced from a collection of dairy farms, on arrival at a commercial rearing unit
• assess the impact of different grouping strategies, based on health assessments or normal farm practice, on calf health and performance outcome

However, due to concerns regarding the physical movement between pens, combined with the handling of calves to allow measurements to occur and an extended period of extremely high environmental temperatures for the geographical location, all of which were stressors on the calves, it was decided that the calves would remain in the groups in which they arrived, and any assessment of grouping strategy would be done on reflection but no physical mixing of calves. Any grouping would still be based on the arrival clinical and respiratory health.