During pregnancy and early lactation cows face large mineral and metabolic demands.
To cope with these demands cows mobilise calcium from bone and fat from energy stores, which can increase the risk of disease and inflammation. In this study we followed 30 dairy cows from late pregnancy through lactation and measured simple blood markers of bone breakdown (CTX‑I), bone formation (osteocalcin), energy use and ten immune signalling proteins (cytokines). Serum CTX-I levels peaked around calving and early lactation, while osteocalcin increased mid‑lactation. Interleukin-6 a pro-inflammatory cytokine that promotes immune responses increased with CTX-1 during late pregnancy, while interferon gamma and interleukin-4 fell as CTX-1 declined. This study helps us to better understand how cytokine production and bone metabolism change around varying stages of pregnancy, birth and lactation in commercial dairy cows.