An investigation into the effect of pooled transition milk quality on preweaning calf health and growth

To capture the health and growth benefits associated with extended colostrum or transition milk feeding in neonatal calves, many large dairy herds pool excess colostrum and transition milk (milkings 2–6 after calving) for feeding. In an observational cohort study of 251 calves, higher passive immunity was associated with lower mortality and morbidity, and improved growth. Each additional g/L of immunoglobulin G reduced the odds of mortality by 12% and the odds of requiring treatment by 11%. Transition milk quality was also significant, showing that calves with low serum immunoglobulin G receiving greater than 5.3 g/L immunoglobulin G or 11.5–12.0% Brix over 10 days had reduced odds of mortality, and those receiving an average of 9.4 g/L immunoglobulin G or 12.5–13% Brix grew faster than those receiving lower quality transition milk. Practitioners must consider quality, duration of feeding and disease transmission when consulting on pooling and feeding transition milk to neonatal calves.