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

This study examines the presence and decline of immunoglobulin G (IgG) in the colostrum (pre-milk secreted during late pregnancy) of mares, revealing differences in the IgG concentrations and disappearance rates between Arabian and Thoroughbred mares.

Objective and Participants

• This study aimed to understand the levels and rates of decrease of IgG in the colostrum of Arabian and Thoroughbred mares from pre-to post-partum period. The study involved 14 Arabian and 22 Thoroughbred mares.

Data Collection

• Colostral samples collected before and after the mares gave birth were examined for IgG concentration. Initial samples gathered from 3 to 28 days before the mares foaled contained over 1,000 mg of IgG/dl.

Findings

• The average concentration of IgG in the Arabian mares’ colostrum at the time of parturition (birth) was found to be significantly higher (9,691 mg/dl) than the average for the Thoroughbreds (4,608 mg/dl).
• The time it took for colostral IgG levels to decrease to 1,000 mg/dl post-foaling was significantly longer for the Arabian mares (average of 19.1 hours) compared to the Thoroughbred mares (average of 8.9 hours).

Effects of Oxytocin

• The researchers also studied the effects of inducing parturition by oxytocin injection on the colostral IgG levels. However, they found that oxytocin did not significantly affect the IgG concentration at the time of birth or the rate at which it decreased thereafter.

Implications

• The results suggest that there may be breed-specific differences in colostral IgG appearance and disappearance. This could potentially influence the early immunity of the foals, depending on the breed of the mare.