Times of appearance and disappearance of colostral IgG in the mare.

Abstract

Pre- and postpartum colostral samples collected from 14 Arabian and 22 Thoroughbred mares were examined for color, consistency, and immunoglobulin (Ig)G concentration. Initial samples, obtained 3 to 28 days before mares had foaled, contained greater than 1,000 mg of IgG/dl. Mean concentration of IgG in colostrum of the Arabian mares at the time of parturition (T0) was 9,691 mg/dl and was significantly (P less than 0.05) higher than the average, 4,608 mg/dl, for the Thoroughbreds. Average times lapsed from T0 until the colostral IgG decreased to 1,000 mg/dl (T1,000) was 19.1 hours for the Arabian mares and 8.9 hours for the Thoroughbred mares--the former being significantly (P less than 0.01) longer. Induction of parturition by injection of oxytocin had no significant effect either upon the colostral IgG concentration at T0 or upon the T1,000.