Abrupt dietary changes between grass and hay alter faecal microbiota of ponies.
Authors: Garber Anna, Hastie Peter, McGuinness David, Malarange Pauline, Murray Jo-Anne
Journal: PloS one
Summary
# Editorial Summary When ponies are abruptly switched between pasture and hay-only diets—a common management scenario—their faecal microbiota undergoes significant compositional shifts that may predispose them to digestive upset. Garber and colleagues analysed faecal samples from six ponies over 14-day periods following abrupt dietary transitions in both directions, using 16S rRNA gene sequencing to characterise microbial populations and their relative abundances across multiple timepoints. Whilst overall microbial richness and diversity remained similar between hay-only and ad libitum grass feeding, the proportional composition differed markedly; notably, transitions from hay to grass triggered a pronounced spike in Lactobacillus species (family Lactobacillaceae) by day 2, suggesting this direction of change provokes a more pronounced microbiotic response than grass-to-hay shifts. The direction of dietary change appears to matter substantially in the immediate post-transition period, with hay-to-grass switches representing potentially greater risk for dysbiosis-related complications. For practitioners managing ponies through seasonal or management-driven diet changes, this research underscores the value of gradual transitions rather than abrupt switches, particularly when moving animals from hay onto fresh pasture where the microbiotic disruption appears most acute.
Read the full abstract on PubMed
Practical Takeaways
- •Avoid abrupt transitions between pasture and hay; the direction of change matters—hay to grass transitions pose higher colic/digestive disturbance risk than grass to hay changes.
- •Monitor ponies closely for the first 2-3 days after any sudden dietary switch, as this is when microbial disruption is greatest and clinical signs most likely.
- •When possible, implement gradual dietary transitions over 7-14 days to allow microbiota stabilization and reduce digestive upset risk.
Key Findings
- •Abrupt dietary changes from grass to hay and hay to grass both significantly alter faecal microbiota composition in ponies within 1-3 days.
- •Hay to grass transitions showed increased Lactobacillus abundance on day 2, suggesting potential for greater gut disturbance compared to grass to hay transitions.
- •Richness and phylogenetic diversity remained similar between hay-only and grass ad libitum diets, but relative abundances of individual taxa differed significantly.
- •Faecal microbiota changes were most pronounced in the first 2-3 days post-dietary change, with stabilization by day 7-14.