Colostrum feeding shapes the hindgut microbiota of dairy calves during the first 12 h of life
&NA; This study evaluated the effect of feeding non‐heated and heated colostrum on the mucosa‐ and digesta‐associated microbiota in the colon of dairy calves during the first 12 h of life. Thirty‐two neonatal Holstein male calves were fed: no colostrum (NC, n = 8), non‐heated colostrum (FC, n = 12) and heated colostrum (HC (60 °C, 60 min), n = 12) immediately after birth. The abundances of mucosa‐ and digesta‐associated total bacteria were higher in the colon of FC fed calves compared to those fed no colostrum (NC) at 12 h of life. Compare to NC calves, a higher proportion of mucosa‐ and digesta‐associated Clostridium cluster XIVa and Bifidobacterium, and a lower abundance of mucosa and digesta‐associated E. coli were detected in the colon of FC and HC fed calves, as well as a tentatively lower relative abundance of Escherichia‐Shigella genus in colon mucosa of HC fed calves. In addition, HC calves had lower abundances of E. coli and higher abundances of Bifidobacterium in mucosa‐associated microbiota than FC fed calves. Our results suggest that feeding non‐heated colostrum immediately after birth benefit neonatal calves with increased Bifidobacterium and decreased opportunistic pathogenic E. coli and Escherichia‐Shigella genus in the colon, and feeding heated colostrum can fortify such effects. &NA; Graphical Abstract Figure. Feeding colostrum shapes the colon microbiota to have higher beneficial and lower opportunistic pathogenic organisms, which may play an important role in enhancing gut health of neonatal dairy calves.