Towards herd-specific udder health management
This text summarizes a PhD project investigating why mastitis remains a major challenge in modern dairy production despite decades of intervention and well-established control strategies. Both clinical and subclinical mastitis continue to cause substantial economic losses, reduce productivity, increase greenhouse gas emissions, and negatively affect animal welfare. At the same time, dairy farming in industrialized countries has undergone major structural changes. Increasing herd sizes and greater reliance on hired employees have shifted the role of the dairy farmer from hands-on animal care toward leadership, training, and supervision. As a result, communication between dairy farmers and herd veterinarians has become increasingly important, yet it remains a key barrier to effective mastitis control. The overall aim of this PhD project was to identify improvement points for herd-level udder health consulting by Danish dairy veterinarians, with particular emphasis on communication, employee management, and microbiological insights.
The first part of the project examined communication between dairy farmers and herd veterinarians and its association with bulk tank somatic cell count (BTSCC) in 88 herds. Both groups completed questionnaires evaluating their perceptions of recent udder health discussions. Agreement between farmers and veterinarians, assessed using Cohen’s weighted kappa, was very low, indicating substantial misalignment between veterinarians’ focus and farmers’ preferences. In contrast, general cooperation between farmers and veterinarians was associated with a statistically significant increase in BTSCC, suggesting that cooperation alone does not ensure improved outcomes if goals and priorities are not aligned.
The second part of the project focused on human resource management and its impact on udder health. A questionnaire assessed how farmers managed employees responsible for milking and examined associations with new intramammary infection rate and BTSCC. Herds with standard operating procedures (SOPs) but no structured training showed a slight increase in new infection rate, whereas herds that implemented herd-specific SOPs through training showed a slight reduction. The findings indicate that SOPs alone do not automatically improve udder health outcomes. However, SOPs may provide reassurance to farmers facing challenges such as time pressure, stress, language barriers, or diverse employee backgrounds. Supporting evidence from previous studies showed higher milk production in herds with implemented milking SOPs. Importantly, providing only generic SOPs without training was associated with a significant increase in BTSCC, emphasizing the importance of proper implementation.
The third part of the project analyzed microbiological data from quarter milk samples collected from newly and chronically infected cows. Using Dairy Herd Improvement data, more than 6,700 samples were classified and analyzed. A strong correlation was found between newly and chronically infected cows, highlighting the importance of internal biosecurity. Microbial diversity was assessed using Simpson’s Diversity Index and the Shannon–Wiener Index. Significant differences in microbial diversity were observed both between herds and between newly and chronically infected cows, indicating substantial variation in infection dynamics and pathogen ecology at the herd level.
Overall, the PhD project demonstrates that effective mastitis control requires more than technical recommendations. Aligning communication between farmers and veterinarians, addressing employee management as a central risk factor, and incorporating microbiological diversity into herd-specific assessments are essential for improving udder health consulting and outcomes.
Michael Farre has a background in dairy farming and veterinary medicine. He earned his Doctor of Veterinary Medicine degree from the Royal Veterinary and Agricultural University in Copenhagen in 2005 and holds certifications in Herd Health Management, and an MBA in Economics and Strategy. He is the only veterinarian in Denmark with the protected title Specialist in Udder Health and Milk Quality. He recently completed his PhD, Towards Herd-Specific Udder Health Management, with a strong focus on practical, on-farm implementation.
