Eight litters of nine pigs each were employed to delineate the length of time after birth that the baby pig is capable of absorbing antibodies from orally ingested colostrum milk containing Escherichia coli antibodies. A sensitized sheep red blood cell hemagglutination test was used to detect the presence of the antibodies contained in the serum. It was found that the baby pig efficiently absorbed the E. coli antibodies at a very young age. This efficiency declined rapidly, following the first order reaction rate law, with a half-life absorption efficiency of 3 hr. Antibody absorption declined to insignificant amounts in baby pigs beyond 24 hr of age.