Dairy cows face several stressful events during the transition period. Among other metabolic problems there are physiological challenges, that predispose them to ketosis and hypocalcemia. Hormonal changes (i.e. estrogen, cortisol, etc.) associated with calving impair their immunity, with higher risk of developing mastitis and metritis.
The process of calving itself further results in inflammation which can predispose to other ailments. While an inflammatory reaction is important to fend-off bacteria, detach the placenta, and repair damaged tissues, it can also lead to profound discomfort and affect the well-being of the cow. The use of potent anti-inflammatory drugs has been associated with increased incidence of retained placenta, higher incidence of post-calving fever, and clinical metritis.