Abstract
Normal adult horse serum was analyzed by electrophoretic and immunoelectrophoretic methods. Seven different protein bands were found by cellulose acetate electrophoresis, 20 fractions by polyacrylamide gel electrophoresis, and a total of 20 antigenic components by immunoelectrophoresis developed with antiserum to normal adult horse whole serum. Changes in the serum proteins, especially the immunoglobulins, IgG, IgG(T), and IgM, and fransferrin, with the advance in age were determined by electrophoretic analyses and a quantitative immunodiffusion method. Precolostral foal serum was almost entirely deficient of immunoglobulins. Very soon after the first ingestion of colostrum, the levels of IgG(T) and IgM of the foal reached a maximal level, which was lower than the mean adult level, while the IgG level of the foal generally exceeded the adult level. Transferrin level was within the adult range in the precolostral serum. It showed no significant changes with the advance in age. On the other hand, all the three immunoglobulin classes and transferrin were high in level in the colostrum collected immediately after parturition, but decreased in level rapidly with the lapse of time after parturition.
