Acute phase proteins as indicators of calf herd health

The potential for using acute phase proteins (APPs) in the assessment of herd health was studied by examining the levels of serum haptoglobin, serum amyloid A (SAA) and plasma fibrinogen in relation to clinical findings and leukocyte counts in calves. Two groups of calves from conventional dairy farms were studied. The animals were examined 10 times during the first six weeks after introduction into a new environment. Haptoglobin, SAA and fibrinogen were analysed and weight gain, disease symptoms and treatments were recorded. Analysis of antibodies against viral infections was performed. An acute phase reaction (APR) score was established at each sampling by combining the APP results and total leukocyte counts. The health status differed between the two groups, although no manipulation of health had been performed, except that the group with a higher incidence of disease had a concurrent experimental infection with lungworm as part of another study. In the group with a higher incidence of disease, the mean weight gain was significantly lower, and the number of sampling days with elevated serum concentrations of APPs, and the mean maximum concentrations of haptoglobin and fibrinogen were significantly higher compared to the healthier group. The APR score was significantly higher at days 4 and 8 of the study in the group with a higher incidence of disease. The results indicate that measurement of APPs could be a useful tool for evaluation of health in calf herds.