Traditional dairy systems remove calves from their mothers soon after birth. Some Scottish dairy farms have explored ‘cow with calf’ (CwC) systems whereby calves are left with their mothers for up to six months, during which time the cow is also milked for human consumption. There may be health and welfare advantages to CwC systems; internationally, work has begun to study these, but no UK work has compared disease incidence and transfer of passive immunity (TPI). Calves must ingest adequate quantities of quality colostrum soon after birth to confer immunity from their dam; failure to do so (FTPI) increases disease susceptibility. Calf colostrum ingestion may differ in CwC systems, thus altering calfhood morbidity and mortality and cow disease risk (e.g. mastitis). This project will compare traditionally reared calves with CwC calves; investigating the incidence of FTPI and of disease in calves and cows in the first three months after calving.