Dynamic changes of rumen bacteria and their fermentative ability in high-producing dairy cows during the late perinatal period.

BACKGROUND

High-producing dairy cows face varying degrees of metabolic stress and challenges during the late perinatal period, resulting in ruminal bacteria abundance and their fermentative ability occurring as a series of changes. However, the dynamic changes are still not clear.

AIMS/METHODS: Ten healthy, high-producing Holstein dairy cows with similar body conditions and the same parity were selected, and ruminal fluid from the dairy cows at postpartum 0, 7, 14, and 21 d was collected before morning feeding. 16S rRNA high-throughput sequencing, GC-MS/MS targeted metabolomics, and UPLC-MS/MS untargeted metabolomics were applied in the study to investigate the dynamic changes within 21 d postpartum.

RESULTS

The results displayed that the structures of ruminal bacteria were significantly altered from 0 to 7 d postpartum ( = 0.486, = 0.002), reflecting the significantly declining abundances of Euryarchaeota and Chloroflexi phyla and , and genera ( < 0.05) and the obviously ascending abundances of , and genera at 7 d postpartum ( < 0.05). The structures of ruminal bacteria also varied significantly from 7 to 14 d postpartum ( = 0.125, = 0.022), reflecting the reducing abundances of , and genera ( < 0.05), and the elevating abundances of and genera at 14 d postpartum ( < 0.05). The metabolic profiles of ruminal SCFAs were obviously varied from 0 to 7 d postpartum, resulting in higher levels of propionic acid, butyric acid, and valeric acid at 7 d postpartum ( < 0.05); the metabolic profiles of other ruminal metabolites were significantly shifted from 0 to 7 d postpartum, with 27 significantly elevated metabolites and 35 apparently reduced metabolites ( < 0.05). The correlation analysis indicated that propionic acid was positively correlated with and ( < 0.05), negatively correlated with ( < 0.01); butyric acid was positively associated with , and ( < 0.05), negatively associated with ( < 0.01); valeric acid was positively linked with and ( < 0.05); pyridoxal was positively correlated with and ( < 0.05) and negatively correlated with ( < 0.01); tyramine was negatively linked with ( < 0.01).

CONCLUSION

The findings contribute to the decision of nutritional management and prevention of metabolic diseases in high-producing dairy cows during the late perinatal period.