Assessment of the immunocrit method to detect failure of passive immunity in newborn foals

Abstract

Background: In newborn foals the absorption of colostrum immunoglobulins in the small intestine is maximal up to 8 hours after birth and then progressively decreases to become null after 24 hours post-partum. Thus, equine practitioners need a simple, quick, inexpensive and reliable field test to identify foals affected by failure of passive transfer rather than an accurate method yielding quantitative results within the whole range of immunoglobulin concentrations. Objective: As the validity of the immunocrit method to detect failure of passive transfer in foals had not been evaluated before, the objective of this study was to test the ability of this method to detect the concentration of immunoglobulins in a large number of foal serum samples. Study design: Assay validation using samples collected for clinical purposes. Methods: The immunocrit test, using a 40% ammonium sulphate solution, was used to measure the concentration of immunoglobulins in serum samples from 211 newborn Thoroughbred foals. The results were compared, by statistical analysis, with those of agarose gel electrophoresis, a reference quantitative method. Results: The values obtained by the immunocrit method were significantly correlated (R =.871; P