Microbiology and Immunology· 2026Q2
Variation in the Milk Microbiota of Healthy Dairy Cows Across Parity and Lactation Stage
- 0citations
- Q2SCImago
- 2026year
Short summary
Milk microbiota in healthy dairy cows shows significant sample-to-sample variation, with two main community types identified: one high in Clostridia and another dominated by Gammaproteobacteria (including Escherichia/Shigella), but this variation is not systematically linked to parity, lactation stage, or udder quarter position.
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Key points
- Milk microbiota in healthy dairy cows exhibits significant sample-to-sample variation.
- Two main bacterial community types were identified: high-diversity (Clostridia-rich) and low-diversity (Gammaproteobacteria-rich).
- Parity, lactation stage, and udder quarter position did not show systematic effects on milk microbial diversity.
- Escherichia/Shigella was a predominant genus in some low-diversity samples.
AI-generated from the title and abstract; the full text is not read.
Abstract
ABSTRACT To characterize variation in the milk microbiota of clinically healthy dairy cows, milk samples were collected repeatedly from four cows throughout lactation and analyzed by 16S rRNA gene amplicon sequencing. Alpha‐diversity analysis showed no significant effects of parity, lactation stage, udder quarter position, or the interaction between lactation stage and position. Although sample‐level PERMANOVA indicated significant associations of beta diversity with cow identity and parity, these associations were not supported when the repeated‐measures structure was appropriately accounted for. Restricted‐permutation PERMANOVA showed no significant effects of lactation stage, udder quarter position, or their interaction, and exact permutation testing at the individual‐cow level showed no significant effect of parity. Ordination and hierarchical clustering analyzes nevertheless revealed substantial variation in bacterial community composition among individual samples. Hierarchical clustering based on genus‐level relative abundance separated most samples into two major groups characterized by relatively high and low diversity. The high‐diversity group showed a relatively high abundance of the class Clostridia, whereas the low‐diversity group was characterized by a predominance of Gammaproteobacteria, particularly Escherichia / Shigella in some samples. Overall, the milk microbiota of healthy dairy cows showed substantial sample‐to‐sample variation, but the present data did not provide clear evidence that parity, lactation stage, or udder quarter position systematically influenced microbial diversity. These findings provide baseline information on variation in the milk microbiota of healthy dairy cows and highlight the importance of accounting for repeated measurements and individual variation in studies of the bovine milk microbiota.
The authors' abstract, as published at the source. Microbiology and Immunology, 2026 · DOI ↗
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Field: Agronomy and Crop Science
Agronomy and Crop ScienceAgricultural and Biological Sciences