Researchers continue to learn more about pre-weaning growth rate and its effect on immune function of calves.
A study in the January Journal of Dairy Science found that a growth rate exceeding 2 pounds per day did not enhance young calves’ immune response to vaccination.
The researchers adjusted milk-replacer intakes to achieve growth rates of 0.24 pounds per day (maintenance), 1.3 pounds per day or 2.6 pounds per day. Calves were not offered starter grain. All calves, regardless of rate of gain, had similar responses to vaccination.
Data from the study also suggest that very high growth rates are associated with reduced viability of immune cells called T lymphocytes or T-cells. These immune cells play a pivotal role in the calf’s response to vaccination and infection.