Capacity for immunoglobulin G (IgG) absorption in the gastrointestinal tract of newborn calves erodes with time after birth and ceases between 24 and 48 h of age. Loose tight junctions in intestinal epithelium and endocytosis via the neonatal Fc receptor (FcRn) have been suggested as possible mechanisms of IgG absorption. The objective of this experiment was to compare gene expression of FcRn and tight junction protein, ZO1, in intestinal sections of calves up to 48 h of age. Bull calves (n = 16) were removed from their dam and slaughtered at 0, 12, 24, or 48 h of age (n = 4/age). All calves except those slaughtered at birth received 4 L of colostrum within 4 h of birth. Calves slaughtered at 48 h also received milk replacer at 24 and 36 h. Cross sections were collected from the duodenum, jejunum, ileum, and colon, rinsed in deionized water, and snap-frozen in liquid N. Total RNA was used to create cDNA and real-time polymerase chain reaction was performed. Fold changes in expression were normalized, first to geometric mean values for 2 housekeeping genes, and then to average values from the same intestinal section of calves slaughtered at birth. Data were ranked and mixed model analysis included intestinal section and calf age as fixed effects, and calf as a random repeated effect. Expression of FcRn and ZO1 differed by intestinal section and FcRn expression tended to increase with time after birth. Mean (±SEM) fold changes in ZO1 expression were 1.05, 0.95, 1.14, and 1.02 (±1.04) in duodenum, jejunum, ileum, and colon, respectively. No differences were observed with calf age. Mean fold changes in FcRn expression were 2.14, 2.53, 2.35, and 1.99 (±0.45) in duodenum, jejunum, ileum, and colon, and 1.27, 1.63, 2.70, and 3.41 (±0.63) at 0, 12, 24, and 48 h, respectively. Intestinal expression of FcRn was lowest at birth, whereas capacity for IgG absorption is greatest at birth; therefore, it is unlikely that FcRn is a major route for IgG absorption in neonatal calves. Tight junction formation as indicated by ZO1 expression was highly variable and not related to time after birth. Subsequent studies of protein expression are needed to confirm these results.