When you get sick, your body fights the infection by producing immune cells.
Cows are no different — their bodies create immune cells whenever there is infection or disease. These cells include white blood cells, also known as somatic cells.
Somatic cells show up throughout the body as part of the cow’s natural defense system, which means they are in the milk the cow produces.
You can measure somatic cells in the milk. It’s good if the cow has somatic cell counts of 100,000 or less — it means the cow is probably free of a particular form of infection known as mastitis. But as counts go higher, it could be a sign of mastitis.
It’s difficult to keep every cow at this level. But it is possible to keep the herd average at 200,000 or below if everyone pitches in and does a really good job. That should be the goal.
When somatic cell counts rise much higher than 200,000, it means two things:
The herd is not as productive as it should be.
Milk quality is suffering.
Research has shown as the somatic count number goes up, the herd loses more milk. If the herd averages a somatic cell count of 400,000, it is losing approximately 3 pounds of milk per cow per day, compared to having no mastitis at all. When somatic cell count rises to 800,000, the loss increases to about 4.5 pounds per cow per day.
Those losses can really add up over hundreds of cows!
And, everyone down the line pays a price. The people who make cheese can’t get as much cheese out of milk that is high in somatic cell count. The taste of the milk may suffer. And, high-somatic-cell-count milk will spoil faster if it sits on store shelves too long.
Some cheese plants offer more money for milk that is low in somatic cell count, or else penalize producers for milk that is high in somatic cell count.
That is why the farm owner insists on keeping somatic cell count low — it really does make a difference.
What is mastitis?
If you fall down and scrape your arm, you may get an infection — especially if dirt and bacteria get into the wound.
Cows have their own form of infection known as mastitis. It occurs when certain germs get onto the teat ends of the cow and then work their way into the udder.
There are two forms of mastitis:
Environmental mastitis occurs through environmental contact. For instance, a cow may come into contact with bacteria in a free-stall barn by being around manure or contaminated bedding.
Contagious mastitis usually occurs in the milking parlor when cows come into contact with milking equipment that has been contaminated by other cows.
In each case, cleanliness is very important.
You want to keep the teats as clean and dry as possible.
So, when the boss tells you to pre-dip and then wipe off the teats thoroughly before milking, he is doing it for a reason.
You may also be asked to “strip” the teats prior to milking. This is to see if cows have clinical mastitis or not. Cows with clinical mastitis have abnormal milk and signs of disease, and you need to let the boss know which cows these are so they can receive treatment.