Spotlight on BMSCC

By John Spearpoint

The hidden cost of subclinical mastitis

The impact of long-term, chronic infections is often not recognised and subclinical infections could be stealing profits. On average, for every 100,000 cells/mL in BMSCC there will be approximately 15% of cows with a subclinical infection.

• Reduced milk yield. Underlying infections reduce overall milk yield and can damage milk secreting cells and tissues. Studies report milk yield drops 2.5% for every 100,000-cell increase in the SCC above a base figure of 200,000 cells/mL.

• Reduced milk price. Milk processors don’t want high cell count milk because it reduces both the shelf life of dairy products and quality and quantity of milk protein in cheese. If your BMSCC is at the upper end, you may be missing out on milk processor incentives.

• Reduced survivability in herd. Lower milk–producing cows with high SCCs are often culled.

• Lower fertility. Studies have shown cows with subclinical mastitis have longer calving-to-first-service and calving-to-conception intervals and more services per conception. The more severe the mastitis, the greater the impact on reproductive performance.

Overall net gains can be achieved by lowering average BMSCC.

Herds that have been able to consistently drive down BMSCC adopt these practical steps.

• Act on herd testing data. Following herd tests identity, high SCC cows and milk samples to determine if there is a bacterial infection requiring treatment. If staph cows are identified, these are culled or milked separately to the main herd to reduce further transmission.

• Monitor milk tanker dockets. A sharp rise may indicate a missed clinical mastitis case. Set a ‘threshold for concern’ where BMSCC exceeds a specific level or shows an upward trend. This level will be different for each farm but becomes a trigger point for further investigation.

• Regular hand stripping the herd. The frequency of this depends on individual farm priorities, with some stripping weekly early in the season to monitor for missed mastitis cases.

• Engage with the milking team. Having everyone on the same page ensures compliance with milking protocols and understanding when mastitis and BMSCC becomes a problem.

• Consider staff financial incentives for lowering BMSCC or keeping within acceptable limits.

• Monitoring teat spray effectiveness. This is one of the most effective SCC and mastitis control measures available, but it only works if it is done properly. Failure to cover the whole teat of every cow at every milking and incorrect teat spray mixes are the most commonly seen errors with teat disinfection.

• Engage with your vet - a second pair of eyes can help identify problems. Our RVC technicians can perform udder health checks and milk sampling high SCC cows.

Milk sample high SCC cows

Milk sampling after herd testing is recommended to identify if there is a bacterial infection requiring treatment. Cows with repeatedly high SCC on successive herd tests are considered chronically infected and unlikely to cure.

• Mastatest high SCC cartridges can be used on-farm for small numbers.

• DairySmart milk culturing. RVC now has an inhouse Jupiter machine for reading larger numbers of milk cultures. RVC technicians can assist with milk sampling larger numbers with results available within 24 hours.

Call your primary vet to discuss options or to assist with mastitis training new staff.