What is a Somatic Cell and How Should It Be Interpreted?
Interpretation of somatic cell counts and can SCC fall too low?
This is a question frequently asked by producers trying to obtain the best milk quality.
A high somatic cell count (SCC) is undesirable in terms of milk quality and mastitis control, but some producers also fear that too low a SCC may cause mastitis cases due to low bacterial fighting capacity.
Somatic cells are white blood cells that fight infection and repair tissue damage. When the udder becomes infected, white blood cells move into the udder and milk to defend against invading bacteria. This process is very important; If this system did not exist, it would be very difficult to eliminate even mild mastitis cases. Somatic cell numbers in the udder do not reflect the defense cells found in the blood to fight infections. Milk SCC only measures the number of cells in milk. The higher the SCC, the higher the likelihood of mastitis of the udder. The key to preventing mastitis is good management practices and healthy cows that can fight mastitis with a strong immune system when necessary.
Could very low SCC cows be considered at greater risk for mastitis infections?
Ideally, a cow’s somatic cell count should be between 100,000 and 150,000. There is some evidence that cows with numbers below 50,000 respond more slowly to infection. And we always encourage dairy farmers to reduce their SCC for higher production and profitability. Many farms today are achieving an overall SCC of less than 75,000, which was previously unheard of. As farms reduce their SCC below 100,000, they increase the number of low-cell cows in their herds. This may also increase the risk of clinical mastitis. However, the benefits of having a very low SCC far outweigh the risks. The answer is not to increase your SCC, but to maximize immunity and keep the cows in the best environment possible.
Why do low SCC cows develop clinical mastitis, which can sometimes be fatal? Is it due to decreased immunity or opportunistic bacteria?
High SCC cows are often associated with infectious (contagious) bacteria. These infections are often subclinical and go undetected for some time. Clinical mastitis, on the other hand, usually presents with a few flakes, clots, or swellings. Environmental bacteria are often present in these herds because they are opportunistic and cannot compete with the highly invasive infectious bacteria. Low SCC cows generally have low levels of infectious bacteria, and their spread can be limited by good milking procedures and management practices. When such herds become infected, it is usually environmental. These organisms are opportunistic, not invasive, meaning most animals that contract these infections have been stressed and immunocompromised, such as dry cows or early lactation cows. Low SCC cows are not more susceptible to environmental organisms, but the clinical signs tend to be more obvious and attract the attention of producers.
In conclusion; Producers must continue to produce the highest quality milk possible. A low SCC means generating more revenue from more milk, increasing quality premiums and reducing mastitis costs. Keeping your cows healthy with healthy nutrition, a clean environment and good management will reduce the risk of infection. The ultimate winner is the consumer who receives a high quality dairy product.
May your milking be fertile!!!
