Effect of refrigeration in mare colostrum

Abstract

Colostrum is the primary source of passive immunity for neonatal foals, as the epitheliochorial placenta of mares prevents transplacental immunoglobulin transfer. The quality and timely administration of colostrum are therefore critical to foal survival. In certain clinical situations, such as maternal death, rejection, or poor colostrum quality, stored colostrum may be the only viable alternative. This study aimed to evaluate how refrigeration affects immunoglobulin G (IgG) concentrations in mare colostrum over time. Colostrum from 10 healthy mares was collected, frozen, thawed, and then stored at 4 °C. Samples were analyzed at 0, 24, 48, 72, and 96 hours post-thaw using ELISA to quantify IgG levels. The results revealed a significant, nonlinear decline in IgG concentration, with the most substantial decrease occurring within the first 24 hours and again between 72 and 96 hours. These findings suggest that while refrigeration can preserve mare colostrum in the short term, its immunological quality diminishes significantly after 48-72 hours. Therefore, refrigerated-thawed colostrum should ideally be used within 24 hours, and longer-term storage should rely on freezing or lyophilization. These results underscore the importance of proper colostrum management to ensure effective passive immunity transfer in foals