Serum immunoglobulin G concentrations in calves fed fresh and frozen colostrum

Objective-To determine whether serum IgG concentrations in neonatal calves are adversely affected by short-term frozen storage of colostrum. Design-Prospective study. Sample Population-Experiment 1 consisted of 10 pairs of Holstein calves (n = 20) fed matched aliquots of either fresh (n = 10) or frozen and thawed (1 0) colostrum. In experiment 2, 26 Holstein calves were fed either fresh (n = 13) or frozen and thawed (n = 13) colostrum. Procedure-Experiment 1 consisted of calves resulting from observed parturit ions; calves were randomly assigned to treatment groups (fresh or frozen an d thawed colostrum) in pairs. Calves were fed 4 L aliquots of colostrum via oroesophageal intubation at 3 hours of age. Serum IgG concentrations at 2 days of age were compared between the 2 groups by use of a paired t-test. E xperiment 2 consisted of calves resulting from observed parturitions; calve s were randomly assigned to treatment groups (fresh or frozen and thawed co lostrum). Calves were fed 4 L aliquots of colostrum via oroesophageal intub ation at 3 hours of age. Regression analysis was used to determine whether calf serum IgG concentration was a function of colostral IgG concentration and colostrum storage group. Results-Significant differences were rot observed between the 2 groups in e xperiment 1. No significant relationship was observed between colostrum sto rage group and serum IgG concentration in experiment 2. The model that best predicted serum IgG concentrations accounted for 20% of the variability in serum IgG concentration. Conclusion and Clinical Relevance-Frozen colostrum is an adequate source of IgG for calves.