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. The presence of lumps, flakes, blood, etc. must be watched for. Milk that is hotter than normal may be a good indication of a Staphylococcus aureus infection.
Palpate the udder
particularly after milking, when it is easy to detect swelling, and fibrous, hard or injured tissue. Subclinical cases may go unnoticed and therefore testing of milk with California mastitis test (CMT) or any other spot test is necessary. Bacteriological examination of CMT positive samples should be carried out. Diagnosis of mastitis is based on bacteriological and cytological methods of examination. For bacteriological examination, milk samples need to be collected under aseptic conditions and.should be preserved under refrigeration.
Somatic cell count
When swelling occurs, the cow’s immune system reacts by sending leucocytes to destroy the foreign bodies. The somatic cell count in the milk may thus indicates if a cow is fighting infection. For normal milk with a cell count of 50,000 cells per ml, there may by 20% leucocytes and 80% epithelial cells, whereas mastitis infected milk with a cell count of over 500,000 cells per ml, contains 90 to 95% leucocytic cells. Facilities for diagnosis of mastitis are available at ICAR Research Complex for Goa, Ela, Old Goa and Disease Investigation Laboratory, Dept. of Animal Husbandry and Veterinary Services, Tonca, Caranzalem.
Prevention and control
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
4. Culling of animals with therapy-resistant mastitis.
Clean milking habits are important to avoid the spreading of germs or their proliferation. The purpose of hygiene is to prevent the transmission of germs from one teat to another on one cow or from one cowto another.
Washing the udder is hygienic and it has a stimulating effect on milk flow. Adequate washing is especially important to prevent environmental mastitis, caused by coliforms and other microbes from contaminated environments. Badly washed udders contribute to the transmission of microbes rather than to their destruction.
Removing a little milk by hand before machine milking serves to stimulate milk let down and to obtain a milk sample containing a high microbial count. Milking order
It is important to milk infected cows last. If possible, milking order should be as follows: first lactation cows, normal cows, cows with a high cell count and then infected cows. It is important to milk twice a day, even with cows that do not produce a lot. The longer the milk remains in the udder, the greater the risk of infection. The first squirts of milk must not go on the ground. as this will contaminate the bedding and floor.
Postmilking teat dipping
Using a disinfectant teat dip after each milking is a means of diminishing by about 50% the risk of infection by contagious microorganisms like Streptococcus agalactiae and Staphylococcus aureus. Teat dipping prevents populations of these microbes from developing sufficiently between milkings. Teat dipping also discourages flies. It is important that the teat dip contain up to 10% of emollients to increase the suppleness of the teat. It is obviously important to clean and disinfect equipment after milking. Cider or corn vinegar and peroxide can be used as alternatives to phosphoric acid and chlorine.
Hygiene and Safety
Abundant bedding prevents injury to the udder, limits exposure to cold damp floors and limits contact of the udder with manure. Adding lime to the bedding can help in a stable where environmental mastitis is a problem but can also irritate the udder, the teats and the lungs when airborne. It is important to prevent the cows from injuring their udders. The floors should not be slippery when the cows are let outdoors and there should be separators between the cows. Disinfecting the stable twice a year is a good practice.
Outdoors There should not be any mud holes around the buildings or any place the cows have access to. Along the same lines, watering areas should not be allowed to become mucky. Ideally, they should be located on higher ground or gravel or cement platforms used under the drinking areas. There should be no barbed wire left lying around or in areas where the cows could injure themselves. Overpopulation in the stable and fields, particularly with loose housing, should also be avoided, as it increases stress on the animals and risk of contagious mastitis being transmitted.
Changes in feed must be done slowly. Excesses must be avoided, particularly concentrates and nonprotein nitrogen feed. A 1.4 to 1.8 calcium to phosphorous ratio must be maintained, even during the dry period. Selenium and vitamin E supplements may be a good choice if the ration does not provide the necessary minimum.
Culling and Replacement
Replacement: Do not buy infected animals; have them tested before purchasing them and examine the udders. It is better to buy only heifers (heifers generally do not have mastitis) or produce your own replacement animals.
Culling: Cull animals that are severely or repeatedly affected by mastitis. Cows with injured teats that do not heal should be put at the top of the list of animals to cull.
Drying off Periods
It is well known that mastitis often affects cows that have recently gone dry. These animals should not be overfed, particularly during dry periods. First lactation cows, in particular, must also be supervised since they are twice as likely to develop mastitis during the dry period than the others.
- Central Coastal Agricultural Research Institute, Ela, Old Goa, Goa