[Evaluation of immunoglobulin G concentration in colostrum of mares by ELISA, refractometry and colostrometry].

The study evaluated the concentration of immunoglobulin G (IgG) in colostrum samples from mares using ELISA, refractometry, and colostrometry, and found significant correlation between ELISA and the two field methods, making them suitable for evaluating colostral IgG-concentration. The research also analysed IgG concentration kinetics, colostrum volume and the total IgG amount, finding differences between primiparous and multiparous mares.

Methods and Samples

• The research was conducted on 360 colostrum samples and 36 blood samples obtained from warmblood mares.
• The concentration of IgG in the colostrum was observed during the postnatal period using an ELISA (Enzyme-Linked Immunosorbent Assay) – a method commonly used to measure the amount of proteins like antibodies and antigens.
• The ELISA results were then compared with values acquired through refractometry and colostrometry, field-based methods used to evaluate the concentration of substances in liquid samples.

Key Findings

• A significant correlation was found between ELISA and the field methods, refractometry (r= +0.93) and colostrometry (r= +0.88). Thus, the field methods can be used to accurately determine the colostral IgG-concentration in mares.
• The researchers also measured the kinetics of the IgG concentration, the total amount of IgG, and the volume of colostrum within the first 12 hours after birth in 36 mares of different parity.
• Immediately post-partum, first-time mothers (primiparous mares) showed a higher mean concentration of IgG (68 mg/ml) than mares that had given birth before (multiparous mares, 51 mg/ml). However, multiparous mares had a larger mean colostral volume (1020 ml) compared to primiparous mares (527 ml) three hours post-partum. Consequently, the total amount of IgG was less in primiparous mares (31.5 g) compared to multiparous mares (48.5 g).
• In the 1.5 hours following birth, a significant decrease in IgG concentration was observed in multiparous mares, while for primiparous, this took about 3 hours.
• The mean IgG concentration in the blood serum of the 36 mares immediately post-partum was 13.4 plus or minus 3.6 mg/ml. However, no significant correlation was identified between IgG concentration values in the blood and colostrum of the mares.