Resumo

REZZANO, Guillermo et al. Detection of Escherichia coli CS31A-antibodies in colostrum from unvaccinated and vaccinated dairy cows against calf diarrhea in Uruguay. Veterinaria (Montev.) [online]. 2024, vol.60, n.221, e202.  Epub 01-Jun-2024. ISSN 0376-4362.  https://doi.org/10.29155/vet.60.221.3.

Neonatal calf diarrhea (NCD) is a severe infectious disease, distributed worldwide. In Uruguay, the calf mortality rate in dairy farms associated with infectious diseases is high. Colostrum intake constitutes the primary source of antibodies of neonates and correlates with good tracers of health and survival during the suckling stage. Vaccination against NCD improves the colostrum’s immunoglobulin composition in pregnant cows. Its correct consumption ensures the transmission of antibodies to the calf and should prevent or reduce the occurrence and outcome of diseases. Several vaccines against NCD are on the market, containing E. coli bacterin, purified E. coli fimbriae together with toxoids, and viral antigens. E. coli CS31A+ bacterin have been included in some vaccines against NCD. The prevalence of clpG is one of the highest among E. coli virulence genes in calves feces in Uruguay. ClpG is the structural protein of CS31A adhesin. This work aimed to determine the level of anti-ClpG antibodies in the colostrum of Holstein-Friesian cows without vaccination and vaccinated against NCD in Uruguay. The colostrum composition was analyzed to determine the functional state of the mammary gland. Non-significant differences were determined in the colostrum-protein or -lactose composition. The differences in terms of fat were assumed on the average for colostrum. A recombinant ClpG protein was purified using a prokaryotic expression system from E. coli. ELISA analyses showed anti-ClpG antibodies in both groups of bovines, reflecting the natural exposure of cows to E. coli CS31A+ strains. Mixed model analysis showed no variance homogeneity between groups but significant differences in medians of the IgG values between groups of cows. A tendency to increase the amount of IgG against ClpG in the colostrum of vaccinated cows was observed, which can result in a better outcome for the calves if the passive transfer of IgG effectively occurs.

Palavras-chave : Escherichia coli CS31A+; Colostrum; anti-ClpG IgG; Passive IgG transference in calves.

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