Associations between teat apex, milk microbiota, and udder health in primiparous cows: Effects of decontamination in a low biomass context

Ferronatto J.A.; Ramos-Sanchez E.M.; Ganda E.K.; Heinemann M.B.; Gonçalves J.L.; dos Santos M.V.; Arantes J.A.; Duarte V.S.; Guimarães A.S.; Costa M.C.; Joossens M.; De Vliegher S.; Souza F.N.; Della Libera A.M.M.P. · Research in Veterinary Science (2026) · DOI: 10.1016/j.rvsc.2026.106221

Resumen

Recent advances in molecular techniques have enabled exploration of commensal microbial communities that may influence disease development or prevention. The bovine mammary gland is constantly exposed to environmental threats that may lead to mastitis, and the teat apex provides a primary access route for infectious agents, playing a crucial role in the first line of defense against both environmental and cow-associated pathogens. The teat apex may also serve as a reservoir for microorganisms that can cause intramammary infections (IMI). This study aimed to: I) evaluate teat apex and milk microbiota profiles; II) associate teat apex microbiota with udder health indicators in primiparous cows at seven days in milk; and III) investigate the effects of in silico decontamination on teat apex and milk microbiota profiles. Ten primiparous Holstein cows, seven days in milk (DIM), were enrolled. Quarter milk samples were collected for bacteriological culture, microbiota analysis, and SCC assessment, and teat apex swabs were collected simultaneously. Negative environmental controls were included to monitor contamination. Staphylococcus and Acinetobacter taxa were most abundant in milk, whereas Bacillus and Staphylococcus were most abundant in teat apex samples. Beta diversity revealed that the teat apex microbiota clustered more closely with environmental controls (PERMANOVA, p = 0.001) than with milk samples, highlighting substantial environmental influence. Microbiota profiles varied across in silico decontamination thresholds, and associations with udder health indicators were detected only at the 0.8 decontamination threshold using unweighted UniFrac. This first investigation of teat apex and quarter milk microbiota in early-lactating primiparous cows highlights key differences between niches and underscores the impact of environmental contamination.

Instituciones: Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas