Timing is critical in FPT cases because the foal’s gut absorbs most of the antibodies from the dam’s colostrum during the first 12 to 18 hours of life. At 18 to 24 hours postpartum, however, the gut begins to mature and can no longer absorb the antibodies that will help protect him from disease. | Photo: iStock

Foals might be able to walk shortly after they enter the world, but they can’t protect themselves from disease. Born with a naive immune system, they’re designed to get the antibodies (immunoglobulin G, or IgG) they need from their dam’s colostrum—the first milk she produces. Sometimes, however, that doesn’t happen.

In these cases—called failure of passive transfer (FPT) of immunity—the earlier the foal can receive treatment the better. But, one researcher said, current diagnostic testing options are either expensive and technically difficult or take a significant amount of time to produce results. That’s why an international team of researchers teamed up to evaluate whether digital and optical refractometry—evaluating the foal’s serum IgG concentrations—could help detect FPT quickly, reliably, and inexpensively.

They found that “digital and optical refractometers are simple, rapid, and cost-effective methods for assessing FPT in foals with moderate to good accuracy,” said Ibrahim Elsohaby, DVM, MVSc, PhD, a postdoctoral researcher at the University of Prince Edward Island’s Atlantic Veterinary College, in Charlottetown, and the Zagazig University Faculty of Veterinary Medicine, in Egypt