Before colostrum replacer (CR) feeding, each newborn calf was weighed using an electronic scale, identified
using a unique ear tag according to its dam (ID), had its navel dipped in a 7% tincture of iodine solution, and then placed in a small group pen (3.6 × 3.6 m) bedded with fresh straw for 24 h following birth. A 10-mL prefeeding blood sample was collected from the jugular vein using a serum Vacutainer tube (Becton Dickinson, Franklin Lakes, NJ) and then the calves were randomly assigned to 1 of 2 treatment groups: GAC or control (CON).