Colostral immunoglobulin transfer in calves I. Period of absorption.

Termination or closure of intestinal permeability to colostral immunoglobulins in the calf occurs spontaneously with age at a progressively increased rate after 12 h postpartum. Following a normal distribution, mean closure occurred near 24 h postpartum when the calves were not fed. Feeding colostrum shortly after birth resulted in earlier cessation of absorption. The amount of colostrum fed had no influence on closure. A quadratic response surface analysis of starting time on closure showed a significant linear response in all immunoglobulin classes, indicating that as colostrum feeding is delayed, cessation also is delayed up to the time of spontaneous closure. Differences in closure time for the three immunoglobulin classes were not significant.