Predicting somatic cell count standard violations based on herd's bulk tank somatic cell count. Part II: Consistency...

Area of Science:

• Dairy Science
• Agricultural Management
• Statistical Process Control

Background:

• Milk quality is crucial for dairy farm profitability and consumer health.
• Monitoring bulk tank somatic cell count (SCC) is a key indicator of udder health and milk quality.
• Existing methods for predicting future SCC violations may lack sufficient accuracy.

Purpose of the Study:

• To evaluate the effectiveness of statistical process control charts and novel consistency indices for monitoring and managing milk quality on dairy farms.
• To compare the performance of the consistency index method against traditional methods based on past violations.
• To assess the capability of dairy herds in meeting specific SCC standards.

Main Methods:

• Collected daily or every-other-day bulk tank SCC data from 1,501 herds over 24 months.
• Developed and applied 5 different consistency indices to assess herd capability in meeting SCC standards.
• Utilized logistic regression to compare the detection probability and certainty of the consistency index method versus a past violation method.

Main Results:

• The consistency index method demonstrated higher detection probability and certainty for identifying future SCC violators compared to the past violation method across all 5 SCC levels.
• Control charts combined with monthly consistency indices could proactively warn 66-80% of herds about upcoming violations within 30 days.
• The developed tools effectively distinguish between significant SCC changes and random variation, supporting fact-based decision-making.

Conclusions:

• Statistical process control charts and consistency indices offer a proactive approach to maintaining high milk quality on dairy farms.
• These tools enhance the ability to identify herds at risk of non-compliance with SCC standards, enabling timely interventions.
• The study provides dairy farms with data-driven methods for improved milk quality management and process capability assessment.