Preserving udder health remains the main justification for antimicrobial use (AMU) in dairy herds, and adjusting such use is central to minimizing AMU overall. Determining optimal AMU levels and their practical guidelines is complex because AMU is influenced by numerous interrelated factors. To examine the balance between reduced AMU, labor input, and financial outcomes, the bioeconomic stochastic simulation framework DairyHealthSim (DHS)© was employed to model mastitis control in dairy cows. This model was linked to both a mean-variance optimization approach and a marginal abatement cost curve (MACC) analysis. Scenarios considered included three antimicrobial (AM) dry-off protocols, five barn hygiene conditions, five milking hygiene levels, and three milk withdrawal schemes.
The first set of results showed comparable economic returns between the blanket and selective dry-off strategies, though it highlighted the compromise between lowering AMU and increased farmer workload. The second outcome revealed the optimal animal-level exposure to antimicrobials (ALEA). The MACC evaluation indicated that when ALEA dropped below 1.5, the average financial loss reached approximately EUR 10,000 per ALEA unit. Findings emphasize the need for integrated farm-level decision frameworks and bioeconomic assessments to guide effective public health policies.
