As a cornerstone of mastitis control in dairy herds, cows have been treated with long-acting antimicrobials at dry off for decades to reduce intramammary infections (IMI). Antimicrobial dry cow therapy cures existing, and prevents new, IMI effectively. Unfortunately, blanket dry cow treatment results in the prophylactic treatment of healthy animals with antimicrobials. Also, a large proportion of antimicrobial usage in dairy farms is due to dry cow treatment. Governments worldwide therefore put legislation in place restricting the blanket usage of antimicrobials at drying off.
However, guidelines stemming from these policies were never based on the highest scientific evidence possible. Farmers and veterinarians are therefore missing evidence-based guidelines when drying off a cow. This project will have two aims. The first work package will evaluate non-antibiotic interventions aiming to prevent new IMI in healthy cows using a network meta-analysis. This will result in a ranking of the effectiveness of various non-antibiotic dry off interventions. The second work package will optimize existing antibiotic interventions aiming to cure existing IMI using an individual patient data (IPD) meta-analysis. This work package will identify subgroups of cows that are likely to benefit from an antimicrobial dry cow treatment and those that do not require antimicrobial treatment. Both work packages are expected to result in optimized dry cow therapy guidelines, thereby promoting a prudent antimicrobial usage in dairy herds worldwide.