Dairy claves (983 head) were left with their dams to suckle for 1 day following birth. They then were fed 1 liter of pooled colostrum and placed in individual pens. Blood samples from each calf were taken prior to and 24 h following colostral feeding. Analysis of blood for immunoglobulins G and M indicated that 42% of the calves had failed either to suckle or to absorb colostral immunoglobulins from suckling. Concentrations of IgG and IgM in serum of calves prior to bottle feeding ranged from 0 to 63 mg/ml and 0 to 15 mg/ml with means of 11.3 and 2.9 mg/ml. From bottle feeding 1 liter of colostrum, 70% of the calves absorbed colostral immunoglobulins, an average increase of 5.0 +/- 4.5 mg/ml for IgG and 1.3 +/- 1.3 mg/ml for IgM. Some calves did not absorb IgG from either suckling or bottle feeding (11.9%) and 20.8% failed to absorb IgM. Mortality rate for all experimental calves was 3.9%; for 83 agammaglobulinemic calves, 13.3%. The high rate of survival (86.7%) of the 83 agammaglobulinemic calves could be due to the local prophylactic effect of colostral immunoglobulins in the intestine even though closure had occurred.