Mastitis or inflammation of the mammary gland or udder is an economically an important condition in milking animals. Mastitis is a disease that affects a large number of dairy cattle throughout the world. It may affect one or all quarters of the udder and it is manifested in the form of swelling of the affected quarters, change in milk colour and composition, If one quarter is affected 25% milk yield is lost permanently. It may also spread to other quarters also, hence it causes major economic losses to the farmer. High animals are more prone to this condition, if not milked properly. The milk from infected udders contributes to high microbial counts of milk, which in turn is not suitable for the preparation of milk products.
Mastitic organisms are also pathogenic for human beings. Mastitis control is a prerequisite to any of the clean milk production programmes. A subclinical form of mastitis is considered worldwide to be the most persistent and widespread complex of diseases of importance to milk hygiene. Subclinical form occurs 20-50 times more frequently than the clinical forms and causes greater losses, although it cannot be recognized unless applying particular methods of examination. Sources and causative agents There are a great number of microorganisms on and in cow udders.
There are 137 species and subspecies of microbes that can be associated with the mammary gland of the cow. Several of them are part of the normal flora and, with few exceptions, do not cause mastitis. On the contrary, they may protect the udders from an infection caused by pathogenic bacteria. Mastitis may be of bacterial or fungal origin. Several other microorganisms may, however, cause infection in the mammary glands.
The most common, those that cause about 90% of mastitis infections, are given in Table 1. There are contagious microorganisms and environmental microorganisms. Infected cows are the main source of contagious microorganisms, which survive and proliferate on the skin and on teat wounds. They consist of Streptococcus agalacliae, Staphylococcus aureus and Streptococcus dysgalactiae.
Environmental microorganisms (Escherichia coli and other coliforms, Streptococcus uberis) do not remain on the teat. Of late, Listeria monocytogenes has been identified as a cause of bovine mastitis. The main sources of the infection of mastitic pathogens are the infected mammary gland, teat lesions, outer skin and the milking person, utensils. In Goa, mastitis cases are mostly due to Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus sp. The reservoir for the main mastitic pathogens is the infected mammary gland. The organisms multiply and secrete into the milk and spread readily in the surrounding environment.
Mastitis is a difficult problem to comprehend because it is a disease caused by many factors. Microorganisms are responsible for the infection, but for them to enter the mammary glands and establish themselves to the point that they cause an infection, a multitude of factors may be involved. There are many such factors (e.g. hygiene, housing, climate, milking machines, feed, genetics) acting simultaneously. The factors which contribute to the causation of mastitis include-
- Contamination with milker’s hands, contaminated floors, utensils and clothes.
- Presence of high population d~nsity of the causative bacteria in the milking shed.
- Damage to the teat sphincter
- Udder infected with FMD, Pox virus.
- Physical trauma that may accelerate the growth of these causative bacteria.
- Sawdust and shaving used as bedding, which are harbouring E. coli.
- Edema and congestion of udder during parturition.
- Poorly designed housing, uneven faulty surface
- Dirty milking machine
Climate may have a direct and in a direct influence on the onset of mastitis. Exposure to intense cold, draughts, excessive humidity or heat predisposes cattle to mastitis. A particular type of ma~titis often called summer mastitis is caused by biting insects that contaminate the udder with the bacteria. Climate may also have an indirect influence. For example, muddy conditions outdoors caused by abundant rainfall will increase the number of microorganisms and thus increase risks of infection.. read more
Since mastitis is a disease that has different levels of intensity and which may be caused by different organisms, there exists a complete jargon to describe the disease. It is therefore important to be able to recognize the different types of mastitis in order to decide what preventive measures to use as well as what treatment..read more
To diagnose mastitis, it is necessary to learn how to distinguish between the symptoms of the various types of mastitis infection. The key points to remember are as follows: Monitor the milk: a routine examination of the milk using a filter cup to extract the first three squirts before washing (before milking) is undoubtedly the best way to diagnose mastitis…read more
Mastitis control also entails a good understanding of the factors that encourage its incidence and the microorganisms that cause it. Mastitis control must be concentrated on the prevention aspects, which depends mainly on the whole hygienic management and absence of stress conditions. Specific control measures need to be taken according to the respective cause and the extent of losses. Specific control measures include-
1. Correction of milking technique
2. Teat disinfection (e.g. teat dipping) following milking.
3. Antibiotic treatment at drying off
There is a vast range of curative methods that may be used as an alternative to antibiotics: homoeopathy, phytotherapy, etc. The advantage of homoeopathy over antibiotics is that milking may be continued. The other alternative products used must not go in the bulk milk because tests for detecting antibiotics in milk may react positively to certain products like some essential oils..read more
- Central Coastal Agricultural Research Institute, Ela, Old Goa, Goa