Subacute rumen acidosis (SARA) is a common dairy herd health issue. Variation among cows in the severity of SARA is a chance to understand the etiology of SARA and prevent the disease. The aim of this study was to determine the relationship between the severities of SARA in the first lactation with that in the second lactation in terms of reticular pH metrics, microbiota and systemic health. Our results showed that individual SARA severity classified based on pH metrics is not transferred from the first to the second lactation in terms of pH metrics, while classified cows still differ in ruminal fermentation and microbiome composition. Our study also showed that feeding a 65%-concentrate diet poses a threat to animal health, independent of classified SARA severity.

Read the full article in the Journal of Animal Science.