Regular individual cow SCC enable you to monitor udder health of each cow over a lactation.
They allow you to assess the contribution of an individual cow to the bulk milk SCC, if problems arise.
They also provide you with options when deciding your dry cow treatment strategy and culling list.
Individual cow SCC
SmartSAMM recommends a minimum of bi-monthly herd testing, which generally equates to 4 tests per seasonal lactation.
Check your Mastitis Focus report for an accurate overview of udder health in your herd. It helps you identify problem areas and potential risks as well as tracking progress after any management changes are made. Contact your herd test provider for more information.
12.1 - Consult your advisor for advice on management of cows contributing high numbers of cells to the vat.
If you are approaching bulk milk SCC penalty levels, take action.
Divert high SCC milk from the vat by:
- Finding and excluding undetected clinical cases
- Excluding high SCC cows from supply - this is a short term solution only
- Drying off individual quarters of specific cows and making her a "3-titter"
- Drying off individual cows early
- Culling high SCC cows.
Excluding certain cows dramatically reduces SCC As a general rule of thumb, excluding up to 10% of the cows will reduce the bulk milk SCC by up to 50%, and milk volume by only 10%.
Seek help Discuss with your vet which cows to exclude from supply, and the options for high SCC cows. It is not considered economic to treat high SCC cows with antibiotics during lactation; only treat on clinical signs.
See Guideline 5.2 for more on stripping the herd to find clinical cases. See Technote 12 for options for dealing with high SCC cows.
12.2 - Consider milking chronically infected cows last to avoid contaminating other cows
In larger herds it is often feasible to manage the high SCC cows in a separate herd and milk them last.
Some electronic identification and drafting systems may allow high SCC cows to be drafted out before milking, and milked last.
See Guideline 8.4 for more on reducing spread of infection during milking, by milking separate herds.
12.3 - Watch for evidence of spread of infection in the herd by checking percentage of cows and heifers with increased cell counts after each herd test
Check the percentage of cows and heifers with increased SCC after each herd test. This gives a simple indication of the spread of infection.
Heifers as an indicator group
At least 85% of the heifers should stay below 120,000 cells/mL for the whole season, if spread of infection is well controlled in a herd.
New Infection Rate
Check the new infection rate on your Mastitis Focus report. This indicates how quickly infection is spreading to clean cows. This is usually not obvious as most mastitis infections are subclinical.
The new infection rate can only be measured in herds that participate in herd testing. Accuracy is further increased if clinical mastitis and dry cow treatment records are uploaded to your herd test provider database.