This season, Westland completed targeted monitoring of both bismuth residues and IgG (colostrum markers) in tanker milk. The results provide valuable insight into how cows are being managed during the transition from calving back into supply.

Bismuth Monitoring

Bismuth is a component of many teat sealant products used during the dry period. Our monitoring programme identified:

• 1 out-of-specification (OOS) colostrum tanker during the seven weeks of Colostrum.
• 6 out-of-specification (OOS ) raw milk tankers during the first eight weeks of supply.

While the majority of samples met requirements, these detections indicate that teat sealant management can be improved on some farms. The colostrum tanker result was particularly concerning, as colostrum supplied for collection should not contain milk from cows where teat sealant residues remain present.

Elevated IgG Results

Over the first two months of the season, 42 elevated IgG incidents were identified in raw milk. IgG (Immunoglobulin G) is used as a marker for colostrum and transition milk. Elevated results indicate that cows may have been returned to supply before their milk had fully transitioned to normal milk.

The Common Theme: Although these are different tests, both sets of results point to a similar issue: Some cows are returning to supply too early.

Why It Matters

Whether it's residual colostrum and transition milk (elevated IgG), or residual teat sealant material (bismuth) the risk increases when cows enter the vat before they are fully ready.

Milk quality incidents create risks for:

• Product quality and processing performance
• Customer and regulatory requirements
• Supplier compliance obligations
• Milk quality deductions and follow-up investigations

Teat sealants remain an important animal health tool, and colostrum management remains a critical part of early lactation management. However, both rely on robust on -farm procedures being followed consistently.

Practical Steps to Reduce Risk
Before returning cows to supply:

• Follow teat sealant label instructions carefully.
• Ensure adequate stripping and removal procedures have been completed.
• Keep freshly calved and treated animals clearly identified.
• Do not return cows to supply until milk has fully transitioned.
• Train all staff in calving, colostrum, and teat sealant management procedures.
• Maintain accurate treatment and calving records.
• When in doubt, keep the milk out.

Looking Ahead

Most suppliers successfully manage these risks every season. However, the 42 elevated IgG incidents
and multiple bismuth detections show there is room for improvement across the supply base.

Key Message: Taking a little more time before returning cows to supply is one of the most effective ways to protect milk quality, meet compliance requirements, and avoid unnecessary investigations or deductions.

Together, we can continue to maintain the high milk quality standards expected by our customers, regulators, and industry.