To determine the mechanism of bovine intestinal incorporation of the pathogen, and the pathogenesis of prion protein in the early stage, cows suckling and weaning were orally given a fusion protein of Abeta-EGFP. Abeta-EGFP was incorporated through the villous columnar epithelial cells and accumulated in crypt patches in the ileum of suckling cows. The sites of the uptake and accumulation of Abeta-EGFP are very close to the peripheral nervous system; however, such uptake of Abeta-EGFP was not observed in 6-month-old post-weaning cows. The present study, therefore, suggests that the weaning period is very important for the risk of transmission.