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Monitor individual somatic cell counts to improve herd health

Published on 18 September 2009

The measure of somatic cell count (SCC) is critical in determining udder health. According to the National Mastitis Council, a herd with a bulk tank SCC of 200,000 cells/mL or greater is considered to be producing “abnormal” milk.

Higher counts indicate infection and are associated with decreased production. For example, a herd with a bulk tank SCC of 500,000 can be expected to have 16 percent of its quarters infected with varying degrees of subclinical mastitis, with a 6 percent reduction in milk production.



While routine bulk tank SCC testing is a good measure of the general status of your herd’s udder health, it doesn’t tell you what to do about those high numbers. The valuable information you can get from individual SCC testing is worth your time and effort.

Identifying problem cows, determining factors contributing to high SCC and developing a management plan for them starts with individual cow screening tests and can lead to better treatment success rates and higher premiums.

Because mastitis is frequently subclinical or “hidden,” several tests are available to detect mastitis by estimating the SCC of a milk sample.

“Detecting subclinical mastitis earlier in its process is a top goal of individual SCC testing,” says Dr. Bradley Mills, Dairy Veterinary Operations, Pfizer Animal Health. “If you can catch the infection sooner in individual animals and choose to treat that animal, your treatment success rate will be higher.”

Testing options
“Whether to test composite milk samples or individual quarters depends on each operation’s strategy,” Mills continues. “If you’re going to make the decision to treat an animal, you should screen each quarter and then treat only the quarter(s) with the high cell count. Producers may spend more on upfront diagnostics, but end up saving that in treatment costs.”


Mills notes there are several options available for individual animal testing. For example, the DeLaval cell counter provides accurate results within a few minutes.

Producers take a sample from a quarter, draw the milk into a cartridge, insert it into the cell counter machine and a few minutes later you have an SCC detection from 10,000 up to 5 million. The California Mastitis Test (CMT) also is an option if used properly. Due to its sensitivity, handlers need to be precise in order to get an accurate reading.

Francisco M. Rivas, quality milk manager, Pfizer Animal Health, adds, “If a producer wants to focus on milk quality, there is so much information to be gleaned from individual SCC and milk component tests. Not only can you monitor infection and cure rates, you can also track butter fat and protein ratios, which help pinpoint other issues.”

The key is monitoring the data on a regular basis to get the most value out of it.

“If a producer is monitoring infection rates and individual SCC, he knows which cows are contributing the most somatic cells to a bulk tank,” Rivas explains. “Finding out which cows likely have subclinical mastitis gives producers more options, including pursuing an extended therapy treatment.”

Finding the cows early that are chronically infected may also increase their lifetime value.


“Constant infection can lead to scar tissue that never recovers when a cow dries up, leading to lost production every year,” Rivas said.

Work with your veterinarian to help you with individual SCC testing and to develop and implement a program to successfully control subclinical mastitis in your herd. PD

References omitted but are available upon request at

—Excerpts from Pfizer Animal Health news release