Effect of Shiga toxoid vaccination and vitamin E supplementation on shedding of Shiga toxin-producing Escherichia coli, immunological, health and performance parameters in male Holstein calves

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Cattle serve as the primary reservoir for Shiga toxin-producing Escherichia coli (STEC) and its pathogenic variant, enterohemorrhagic E. coli (EHEC). Humans can contract EHEC through the fecal-oral route via contact with ruminants or consumption of contaminated food. Vaccinating cattle may reduce intestinal STEC colonization and lower fecal STEC excretion, thereby decreasing human infection risk. The virulence factor Stx influences immune responses in cattle, while Vitamin E supports immune function. This study aimed to examine the effects of Shiga toxoid vaccinations and Vitamin E supplementation on immunological parameters and STEC shedding in calves. A total of 24 calves were vaccinated with colostrum from immunized cows and received additional vaccinations, while 24 controls were given low anti-Stx colostrum and placebo injections. The study analyzed data based on Vitamin E levels in milk replacer. Increased Vitamin E supplementation resulted in higher serum α-tocopherol levels and earlier concentrate intake, but did not significantly affect growth or immune cell populations. The transfer of Stx-neutralizing antibodies from dams to calves was confirmed. Vaccinated calves exhibited a stronger immune response to STEC and E. coli strains. While the vaccination altered the CD4+/CD8+ ratio, no additive effects from Vitamin E were observed. Ultimately, fewer fecal samples from vaccinated calves tested positive for Stx. The findi