Colostral whey concentrate supplement increases complement activity in thesera of neonatal calves

We evaluated the effect of a commercial bovine colostral whey on the comple ment-mediated immune responses of calves. Two groups of neonatal calves wer e fed, in addition to whole milk (WM) and pooled colostrum (PC), different amounts of a commercial immunoglobulin concentrate made from pooled colostr al whey (Ig-C) for the first two feedings post natum. The control group was fed WM and PC only. Serum samples were obtained at the ages of 2, 7, 14 an d 30 d. Bacteriolytic activity against complement-sensitive Escherichia col i JM103 and opsonic activity against complement-lysis-resistant E. coli IH3 080 strains were studied, as well as the levels of C3 complement component and E. coli JM103 specific antibodies in the sera. Groups fed Ig-C had 2-3 times higher bacteriolytic activity than the contro l group of both the classic (P<0.005) and alternative pathways (P<0.0001) a t days 2 and 7 post natum. This effect is obviously not caused solely by th e antibodies ingested but also involves other unknown colostral factors, po ssibly lectins. The opsonisation capacities of the sera correlated well wit h the amounts of immunoglobulins ingested (P<0.05) at days 2-14. The levels of C3 component in sera did not differ between the groups. In the group fe d the largest amount of immunoglobulins levels of E. coli JM103-specific an tibodies were highest (P<0.0001). It can thus be concluded that the antibod y independent complement activities of serum can be increased substantially by feeding colostral whey concentrate to calves during their first days of life.