were the foals gums or whites of eyes yellow??? This is important. The foals starts out vigorous and nurses great. Then what happens is, there are antibodies in the mares colostrum that destroy the foals red blood cells. The foal starts to fail, becomes anemic, whites of eyes turn yellow, or gums turn yellow. The foal must not be allowed to nurse but fed another mares colostrum or milk repcement by bottle . You must milk off the colostrum until the regular milk comes in about 24hours. Then the foal can nurse again.
We should always remeber to take some colostrum and mix it with cord blood at birth. If it clumps... this bad stuff will happen. If it blends nicely, the foal can nurse.
Robin