A lack of colostrum may delay postnatal intestinal development in foals. Therefore, in this study, the effect of colostrum withdrawal on duodenal development of newborn foals was investigated. Shetland foals were fed either colostrum (group COL, n = 5) or milk replacer (group MR, n = 8) by nasogastric tube over the first 24 hours of life, and all foals received one liter of hyperimmune plasma. On day 3 of life, duodenal biopsies were taken via gastroduodenoscopy. Expression of mRNA for receptors for insulin-like growth factor 1 (IGF1), IGF2, and transforming growth factor beta (TGF beta) was analyzed by real-time PCR. Biopsies were analyzed for IGF receptors 1 and 2, TGF beta receptor 1, immunostaining for Ki-67 proliferation marker, lectin binding, and histomorphology. The mRNA expression of receptors for IGF1, IGF2, and TGF beta in the duodenum of newborn foals was not altered by withholding colostrum. The number of goblet cells in the epithelium of the duodenum was greater in MR compared with COL foals (1.95% +/- 1.15 vs. 1.25% +/- 0.75), whereas villus length did not differ between groups. Immunohistochemistry of Ki-67 and lectin-binding patterns was similar in foals of both groups. Results indicate that a lack of colostrum is without detrimental effects on postnatal duodenal development in foals. (C) 2015 Elsevier Inc. All rights reserved.