Lowering Somatic Cell Counts in Milk
Emily Wilmes, University of Minnesota
Somatic cell counts are a long-standing marker of milk quality, impacting shelf life and flavor. A lower SCC is better for cheese production and gives a longer shelf life for bottled milk.
The national maximum SCC level is 750,000 cells per milliliter per farm for domestic sales and 400,000 cells per milliliter for exports.
Although somatic cells occur naturally and are not a food safety concern, dairy farmers monitor them because they can be used as a measure of the health of their cows. Processors also pay a premium for milk with low counts. A farmer whose herd has a very low count can receive a significantly higher price per hundredweight compared to a farmer whose herd average is high.
In Minnesota, dairies can receive penalties up to $2.00 per hundredweight for high cell counts. In a time when farmers can’t afford to take any reduction in their milk price, it is important to take steps to avoid any penalties from your milk plant.
There are some simple and practical steps you can take that can help lower somatic cell counts on your farm.
Understand the problem
It is important to understand what the situation is on your farm to best manage the issue.
Bulk tank somatic cell count (BTSCC) is the measure used to test milk quality for a herd. Just a few cows with really high individual SCC can skew the entire bulk tank high.
Many cows in the herd with cell counts that stay high on a long term basis can also raise the bulk count.
On your DHIA report,
look at linear SCC scores,
percent of cows infected by days in milk,
and the "Changes in SCC Status" box.
Be sure to look at individual cow reports. This can help you pinpoint problem cows and potentially make culling decisions.
Culture your milk
Get a sample milk culture to determine what you're really fighting.
Start with a bulk tank culture to find out if the problem is environmental, contagious or something else. The results will narrow down the strategy you should use to combat the issue.
Take bulk tank samples on multiple test days to get the clearest picture of what you're dealing with. Sometimes one organism can overwhelm the plate so much that other present organisms won’t even show up.
Look for consistent culture results to narrow down the problem.
Consider culturing some cows individually, especially those that consistently have high SCC or have new infections.
Controlling contagious infections
Culture results may reveal the presence of contagious organisms like Staph aureus, Strep ag, or mycoplasma. If this is the case, there are a few key steps you can take to help reduce the spread of these organisms when culling is not an option.
Contagious cows should always be milked last to avoid spreading the organisms to non-infected cows.
Move infected cows to a different area of the barn or into a different pen. Keeping these cows separate is crucial to reducing the spread of contagious organisms.
Make sure the teat dip you are using is effective against the problem organisms.
More importantly, determine if you are getting proper teat dip coverage.
Pre-dip should have a contact time of at least 30 seconds with the teat skin surface.
Post-dip should fully cover the teat.
Look at equipment function and cleaning as well as the entire cow prep procedure.
Consider universal dry cow therapy for your herd if you are not already doing so.
Controlling environmental infections
If culture results reveal high counts of environmental organisms, the goal is to create an environment in which is hard for these organisms to survive. It's important to keep cows and their bedding clean and dry.
Add more bedding to stalls or packs and change bedding more often.
It could be worth it to bed twice a day if you notice cows are really getting wet and dirty.
Make sure milking equipment is kept clean and spray off any equipment that may get dirty during milking.
Cleaning teats well during milking prep is critical.
There should not be any dirt or manure present on teats.
Taking the time to make sure teats are fully clean will make a huge difference in the presence of environmental organisms.
Proper pre- and post teat dip also helps fight environmental infections.