Effects of High Concentrate-Induced Subacute Ruminal Acidosis Severity on Claw Health in First-Lactation Holstein Cows.
Authors: Kofler Johann, Hoefler Michael, Hartinger Thomas, Castillo-Lopez Ezequias, Huber Johann, Tichy Alexander, Reisinger Nicole, Zebeli Qendrim
Journal: Animals : an open access journal from MDPI
Summary
Subacute ruminal acidosis (SARA) is a chronic metabolic challenge recognised during transition and early lactation in high-producing dairy cattle, yet its specific effects on claw integrity remain poorly characterised. Researchers induced varying degrees of SARA severity in 24 first-lactation Holstein heifers through high-concentrate feeding (60% dry matter) from calving to day 70 of lactation, using continuous intraruminal pH monitoring to retrospectively classify animals into light, moderate, and severe SARA groups based on the proportion of days pH remained below 5.8 for more than 330 minutes. The severe SARA group demonstrated a significantly higher lameness incidence compared to the light SARA group (p = 0.023), with each additional day of SARA exposure associated with a 2.52% increase in lameness likelihood; notably, white line lesion prevalence increased substantially between mid and late lactation in severely affected cows, though overall claw lesion severity did not reach statistical significance across groups. These findings suggest that whilst high-concentrate diets pose inherent risks to claw health in early-lactation heifers, the cumulative duration of acidotic episodes—rather than concentrate percentage alone—may be a critical driver of lameness and specific lesion types. Practitioners should recognise that sophisticated rumen pH monitoring or biomarkers indicating SARA severity could help identify at-risk animals early, potentially allowing targeted nutritional or management interventions to mitigate claw pathology before clinical signs emerge.
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Practical Takeaways
- •High-concentrate diets that induce SARA significantly increase lameness risk in first-lactation dairy cows; nutritional management during transition and early lactation should prioritize rumen pH stability
- •Severity of SARA exposure matters more than mere presence—cows experiencing SARA on >30% of days showed markedly worse claw health outcomes than those with minimal SARA exposure
- •White line lesions are a delayed manifestation of SARA-induced metabolic stress, emerging weeks after the initial dietary challenge, suggesting preventive hoof care protocols should account for subclinical acidosis effects
Key Findings
- •Lameness incidence was significantly higher in cows with severe SARA (>30% of days) compared to light SARA (≤11%), p=0.023
- •For each day experiencing SARA, the likelihood of becoming lame increased by 2.52% (p=0.0257)
- •White line lesion prevalence significantly increased between 70 and 160 DIM in the severe SARA group
- •Cows in the severe SARA group showed higher mean Cow Claw Scores at all visits, though differences were not statistically significant