Microbial Dynamics of Beef on Dairy Calves During the Neonatal Period

Gut microbiome colonization in newborn calves is key for long-term health, welfare, and productivity across a lifetime. This study aimed to investigate the impact of colostrum feeding on intestinal microbiota dynamics of beef-on-dairy calves during the first 21 days of life. Animals were randomly assigned to a colostrum-fed (n = 12) or a colostrum-deprived (n = 12) group. The colostrum-fed group received 2.8 liters of high-quality colostrum within six hours after birth. At eight days of age, intestinal inflammation was induced via oral inoculation with Salmonella Typhimurium in six calves from each group. Meconium and rectal swabs were collected at birth (day 0), days 7, 8, 9, 10, 11, 14, and 21 of age. Microbiota diversity was analyzed based on 16S rRNA sequencing. Calves that received colostrum had greater microbial richness and diversity compared to colostrum-deprived calves. In response to the Salmonella Typhimurium inoculation, the diversity changes were more prominent in the colostrum-deprived compared to the colostrum-fed group. Our study highlights the importance of maternal colostrum in influencing a resilient and diverse intestinal microbiota composition, which in turn decreases the occurrence and intensity of enteric diseases in beef-on-dairy calves before weaning.