Comparison of serum IgG half lives in dairy calves fed colostrum, colostrum replacer, or administered with intravenous plasma

The cotyledonary placenta allows minimal transfer of immunoglobulins from the cow to the fetus during pregnancy. Consequently calves are born hypogammaglobulinemic, thus making it essential to ingest and absorb colostral immunoglobulins to acquire passive immunity. Therefore, the half-life of maternally derived colostral immunoglobulin G (IgG) in dairy calves is important in the development ofthe calf immune system as well as determination of the age at which to vaccinate the calf without interference from the maternally derived IgG. Half-life of maternally derived colostral IgG is estimated to be 20 days in dairy calves. In clinical settings, bovine plasma is used as part of treatment of sick calves that require additional immunity via plasma administration. Currently, no studies have evaluated the half-life of colostrum replacer derived IgG or plasma derived IgG in dairy calves. We hypothesized that the half-life of maternally derived IgG has a significantly different half-life compared to colostrum replacer derived or plasma derived IgG in dairy calves. The aims of this study were to determine the half lives of IgG derived from colostrum, colostrum replacer or plasma in dairy calves.