Quantitative indirect ELISA-based method for the Measurement of serum IgG in springbok calves

Passive transfer of immunity through maternal colostrum is an important factor in the survival of ruminant neonates, as they essentially lack the ability to receive immunity in utero. Inadequate ingestion of colostrum by neonates can result in increased levels of morbidity and mortality. Several methods are used to determine serum immunoglobu-lin levels, both before and after administration of colostrum or colostrum replacement. Radial immunodiffusion analysis (RID) is generally considered the reference method for determining serum or colostral immu-noglobulins concentrations in ruminants. Unfortunately, RID is labor-intensive, time-consuming, and takes 48 to 72 hours to provide serum immunoglobulin test results. Currently, methods to determine colostral or serum immunoglobulin concentrations in non-domestic ruminants are not available. In this study we describe a method for measuring sera immunoglobulin levels using an indirect enzyme-linked immunosorbent assay (ELISA) that can be completed within one working day. The described method is relatively more accurate, precise, and expeditious and less labor intensive than an RID assay. While this protocol was developed for use with springbok sera, it should be easily adaptable for other non-domestic ruminants species for which commercial antibodies are not readily available.