Mastitis is the inflammation of the mammary gland or udder. Physical trauma or bacterial infections are two main causes of udder infection. If cows are suffering from mastitis their milk has increase somatic cell count.
Somatic cell count (SCC)
Somatic cell count include number of White blood cells (leukocytes), which is released in response to pathogenic bacteria. Generally, it is considered that 100,000 cells/mL SCC is present in an uninfected cow while 250,000 (SSC) indicate that cow is infected with a certain type of pathogens.
In Other words, white blood cells (leukocytes) released into the mammary gland, in order to fight pathogens. Where leukocytes invade into the teat canal or to deal with any type of physical, chemical or mechanical trauma in udder. Pathogens secrete toxins which instantly damage milk secreting tissues. Consequently, it reduces milk quality and yield. Generally speaking, if SCC increases, milk quality decreases.
Mastitis causing microorganisms
Most bacteria which causes mastitis include
Pseudomonas aeruginosa, Staphylococcus aureus (ATCC 12600) ,Staphylococcus epidermidis, Mycoplasma bovis and E.coli etc. These bacteria may be present in environment, they will cause environmental mastitis or contagious mastitis. It totally depends on their source of transmission. Eventually the milk contain more of these bacteria and less likely to contain Lactobacillus acidophil
Identification of Disease
If cow is infected with sub-clinical mastitis, there will not any visible sign of infection appear. Although it reduce milk yield. But if it is clinical, then we can see several signs, like swelling, heat, redness or hardness of udder. Even their milk may appear abnormal having flakes, clots and watery appearance.
Effect of Mastitis on Milk Composition
Milk is composed of 80-82% Casein protein. Rest is 18-20% serum or whey protein. Casein is Phosphate containing protein which has an ability to combine with Calcium and make calcium phosphate. So more Casein protein means it can hold more calcium and ultimately good source for consumer. However, In mastitis milk casein decreases so milk whey protein & immunoglobulins increases, which is why milk appear more watery in mastitis.
Mastitis can cause increase in Lactoferrin. It is an iron-bearing protein, most probably present in milk, colostrum, saliva, tears and nasal secretions etc. As mentioned, this protein binds with free iron ions floating in milk so it inhibit the growth of those bacteria which feed those iron ions. In this way this protein is have antimicrobial activity as well. Below article explain this phenomenon in details: Scienedirect
Treatment and Control
The affected cows can be treated with antibiotics but we can not sell the milk if antibiotic residues are present in it. We should keep those cows separate with red band on their leg indicating other farmer not to use this cow milk and discard it. Vaccines are available as well but they will not reduce the severity of the disease. Dairy workers should take some protective measures to deal with this disease. They should use rubber gloves while milking. Proper milking hygiene should adopt.
They must to keep infected animals separately in order to less likely transmission of the disease. Iodine spray can be use to wipe teats. Moreover, Iodine Propylene-Glycol should use as a disinfectant. One of the major factor is that teat holes close after fifteen minutes of milking and if cow sits on a dirty place having feces and urine it could be a major reason of infection.