High Somatic Cell Counts In Dairy Cows

With dairy cows, oftentimes there is an increase in general stress due to summer heat and humidity. One common outcome is that of c.

Somatic cell counts are a reflection of udder health. Unfortunately, very healthy looking cows can have high somatic cell counts! Somatic cells are basically in the udder to fight infections in the udder (usually germs). The immune system of the cow works within the udder just as it does in other parts of the cow’s body. However, when the immune system is actively at work fighting germs in the udder, the somatic cell count goes up because the white cells of the immune system make up the somatic cells.

The ideal range for cell counts are between 25,000 – 100,000 and this is where you get the highest bonus for milk quality. Between 150,000 and 400,000 is very typical for many producers. When bulk tank somatic cell counts get above 400,000 there are truly problems with udder health. While the organic processors limit milk to be less than 400,000 the legal limit is 750,000. Above 750,000 and the truck will not come to pick up milk as it is a violation of federal law to be above 750,000.

DHIA linear somatic cell count (LSCC) parallels the numbers shown above in this way: LSCC 1 = 25,000; LSCC 2 = 50,000; LSCC 3 = 100,000; LSCC 4 = 200,000; LSCC 5 = 400,000; LSCC 6 = 800,000. The scale goes up to 9 with doubling every number that it moves up. When a bulk tank constantly has an average somatic cell count of 500,000-600,000 +/- this usually indicates that a contagious germ is present (Strep ag or Staph aureus), in the experience of many.

During some stressful times of summer, the bulk tank SCC may be elevated, due to general summer time heat and humidity. However, the SCC should start going down again towards autumn. Since the bulk tank is a reflection of all the milking cows, an average 600,000 that means there are some individual cows with very high counts.

On the opposite side of the spectrum, if bulk tank counts are always extremely low, such as ~50,000 +/- there may be more chance of coliform mastitis occasionally occurring since the immune systems of the cows is generally on “vacation” due to such extremely clean life in the udders of the cows.

One thing to remember is that the bulk tank SCC is an average for the herd while the DHIA data shows individual cows but the CMT identifies the quarter of the cow which is causing problems. Having a CMT kit is essential for good udder management and to know which quarter to use a quarter-milker on to keep it out of the tank.

Culturing milk from a cow’s quarter is the only way to which germ is causing problems. Cows showing a linear somatic cell count of 5 and above should have a CMT run to identify the quarter to culture. Culturing cows is simple and once put in the incubator take about 48-72 hours to have a result.

There are generally two kinds of mastitis germs: contagious and environmental.

The contagious ones are generally recognized to be Strep ag and Staph aureus. Once established in the quarter, these germs thrive and get passed from cow to cow. Oftentimes, Strep ag milk will look fairly normal but have amazingly high somatic cell counts – easily 1-4 million! Strep ag bacteria are simple to kill with antibiotics. Staph aureus will more likely show actual clinical mastitis and trigger the udder to react, walling themselves within abscesses where treatments cannot get at them.

Management of cows known to be infected with a contagious germ requires using a separate milking unit on these cow (if there are many), milking these cows last or as a group, rinsing the milking unit between cows (in water at 180 F), pre-dipping and post-dipping, cleaning the teats (especially the bottom where the sphincter is), wearing latex or nitrile gloves on both hands (and cleansing them or changing them as needed). Actually, these management methods are what are essential for excellent milking hygiene.

In a study that Ken Griswold (an extension agent) did, it was shown that herds using gloves and dipping at milking times had half the somatic cell count as herds that did not. This was from real life information from farm here in the county. I would be confident that other areas would find the same thing.

The environmental bacteria are generally recognized to be coliforms (E. coli, Klebsiella, Pseudomonas) or certain streps (Strep dysgalctia, Strep uberis). These do not like living in the udder as contagious bacteria do, but if they get into the udder, they can cause serious problems. Coliforms are generally from manure. You can maybe remember the word coliform since the word colon (gut) is part of it.

These germs are usually due to poor milking hygiene (not cleaning teats appropriately) and can be found in certain bedding types. Sawdust and ground peanut hulls come to mind. Cows can become terribly sick due to coliform mastitis. Environmental strep mastitis usually causes clinical flare-ups but not terribly sick cows. The same milking procedures as described in the preceding paragraph apply to environmental mastitis problems mainly because they are correct milking hygiene principles.

Many kinds of bacteria are present in the milk as well but usually do not cause mastitis problems. Unfortunately, rare but extremely dangerous bacteria can cause problems in people drinking fresh, un-pasteurized milk. These bugs are E. coli 0157H7, salmonella, campylobacter and listeria.

Creating the best, top quality milk should be every farmer’s goal. Achieving it can be the hard part but should always be priority number one.

PhytoMast tubes (all botanical, OK for organic) are a handy antiseptic which can enhance udder health. Many farmers are using them for recent udder health problems (not E coli and not Staph aureus) or dry off of questionable quarters.

Recent Posts