FARM-LEVEL DIAGNOSIS OF MASTITIS IN DAIRY ANIMALS
Shraddha Sinha
Department of Veterinary Medicine (TVCC), College of Veterinary Science & Animal Husbandry, Dau Shri Vasudev Chandrakar Kamdhenu Vishwavidyalaya, Anjora, Durg, Chhattisgarh, India
Abstract
Mastitis is one of the most common and economically important diseases of dairy animals. It causes inflammation of the udder and affects milk yield, milk quality and farm income. The disease may occur as clinical mastitis, where changes are visible in milk and udder, or as subclinical mastitis, where the animal appears normal but infection is present. Early diagnosis is essential to prevent production loss and spread of infection in the herd. Simple farm-level methods such as observation of the animal, udder examination, foremilk examination, strip cup test and California Mastitis Test are useful for early detection. Laboratory tests such as somatic cell count, milk culture and antibiotic sensitivity testing help in confirmation and proper treatment planning. This article highlights practical diagnostic approaches for mastitis detection in dairy animals.
Keywords
Mastitis, dairy animals, udder health, CMT, somatic cell count, milk culture
Introduction
Dairy animals are an important source of regular income for farmers. Any disease that reduces milk production directly affects farm profitability. Among udder diseases, mastitis is one of the most serious problems in cows and buffaloes. It is mainly caused by microorganisms that enter the udder through the teat canal and produce inflammation.
Mastitis leads to reduced milk production, poor milk quality, treatment cost, discarded milk during therapy and sometimes permanent damage to the udder. In severe or repeated cases, the animal may become uneconomical for the farmer. Therefore, early detection is very important.
Diagnosis of mastitis should not depend only on advanced laboratory facilities. Farmers can identify many cases at the farm itself by regularly observing the animal, checking the udder and examining the first few streams of milk before milking.
Causes and Risk Factors
Mastitis is commonly caused by bacteria such as Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, Escherichia coli and Klebsiella species. These organisms may spread during milking or may come from the environment.
Important risk factors include poor milking hygiene, dirty bedding, wet floor, teat injury, use of common towels, incomplete milking, faulty milking machine and poor housing sanitation. The teat canal remains open for some time after milking; hence, animals should not be allowed to sit immediately on dirty floors after milking.
Types of Mastitis
Mastitis is mainly classified into clinical and subclinical forms.
Clinical mastitis is easy to identify because visible changes are present. Milk may contain flakes, clots, pus, blood or watery secretions. The affected quarter may become swollen, hot, painful or hard. In severe cases, fever, dullness, reduced appetite and sudden drop in milk yield may be observed.
Subclinical mastitis is more difficult to detect because the udder and milk appear normal. However, inflammation is present inside the udder and milk production is reduced. This form is important because it remains hidden and may spread infection silently in the herd.
Importance of Early Diagnosis
Early diagnosis helps in reducing milk loss, preventing spread of infection, improving milk quality and reducing treatment cost. If mastitis is detected early, the chance of recovery is better. Delayed detection may lead to chronic mastitis, repeated treatment failure and permanent udder damage.
Farmers should remember one simple rule: check the udder and first few streams of milk before every milking.
Diagnosis of Mastitis
Diagnosis of mastitis includes farm-level examination and laboratory confirmation. Farm-level methods are useful for early suspicion, while laboratory tests identify the cause and help in proper treatment selection.
Farm-Level Diagnosis
The first step is observation of the animal. Affected animals may show restlessness during milking, kicking when the udder is touched, reduced feed intake, fever or sudden fall in milk yield.
The udder should be examined before milking. Swelling, heat, pain, redness or hardness of one or more quarters indicates inflammation. Teat injuries, cracks or wounds should also be checked because they act as entry points for infection.
Milk examination is one of the simplest diagnostic methods. The first few streams of milk should be checked separately from each quarter. Presence of flakes, clots, pus, blood, watery milk or foul smell indicates clinical mastitis.
The strip cup test is a useful daily screening method. In this test, the first few streams of milk are drawn into a strip cup or dark-bottom plate and examined for visible abnormalities.
California Mastitis Test, or CMT, is a simple cow-side test used mainly for detecting subclinical mastitis. Milk is mixed with CMT reagent in a paddle. Gel formation indicates increased somatic cells and possible udder inflammation.
Table 1: Farm-Level Diagnostic Methods for Mastitis
| Diagnostic Method | Observation | Importance |
| Animal observation | Reduced feed intake, fever, sudden fall in milk yield | Early suspicion of mastitis |
| Udder examination | Swelling, heat, pain, hardness | Detects udder inflammation |
| Teat examination | Cracks, wounds, teat-end injury | Identifies infection entry points |
| Milk examination | Flakes, clots, pus, blood, watery milk | Detects clinical mastitis |
| Strip cup test | Abnormal first milk streams | Daily farm-level screening |
| California Mastitis Test | Gel formation with reagent | Detects subclinical mastitis |
Table 2: Interpretation of California Mastitis Test
| Reaction | Appearance | Interpretation |
| Negative | Watery mixture | No significant inflammation |
| Trace | Slight slime | Doubtful; repeat test |
| Weak positive | Mild thickening | Mild udder inflammation |
| Positive | Clear gel formation | Mastitis suspected |
| Strong positive | Thick jelly-like mass | Severe inflammation likely |
Laboratory Diagnosis
Laboratory diagnosis is useful in repeated cases, severe mastitis, herd outbreaks and treatment failure.
Somatic cell count measures inflammatory cells in milk. Increased somatic cell count indicates udder inflammation and is useful for detecting subclinical mastitis.
Milk culture is used to identify the bacteria causing mastitis. It helps to know whether the infection is contagious or environmental. Contagious mastitis spreads mainly during milking, while environmental mastitis is associated with dirty surroundings, bedding, manure and contaminated water.
Antibiotic sensitivity testing helps in selecting the most suitable antibiotic. This prevents blind treatment, reduces treatment failure and helps control antibiotic resistance. Antibiotics should always be used under veterinary supervision, and milk withdrawal period must be followed strictly.
Table 3: Laboratory Diagnostic Methods for Mastitis
| Test | Purpose | Use |
| Somatic Cell Count | Measures inflammatory cells | Detects subclinical mastitis |
| Milk culture | Identifies causative bacteria | Confirms infection type |
| Antibiotic sensitivity test | Finds effective antibiotic | Guides treatment |
| Electrical conductivity | Detects milk salt changes | Early warning tool |
| PCR | Detects bacterial DNA | Advanced rapid diagnosis |
Proper Milk Sample Collection
Correct sample collection is essential for reliable laboratory results. Milk samples should preferably be collected before starting antibiotic treatment. Hands should be washed properly. The udder and teats should be cleaned and dried. The teat end should be disinfected with spirit swab. First few streams of milk should be discarded. Milk should be collected in a sterile vial without touching the inside of the cap or bottle.
Each affected quarter should be sampled separately. The sample should be labelled with animal number, quarter, date and farm name. It should be kept cool and sent to the laboratory as early as possible.
Common Mistakes by Farmers
Common mistakes include ignoring slight reduction in milk yield, not checking foremilk, mixing abnormal milk with normal milk, using antibiotics without veterinary advice and not following milk withdrawal period. Use of common towels for all animals and poor milking hygiene can also spread infection.
Infected animals should be milked separately or at the end. Milker’s hands should be clean and dry. Milking machines should be checked regularly to avoid teat injury.
Simple Diagnosis Plan for Farmers
Farmers should observe the animal and check the udder daily before milking. First streams of milk should be examined using a strip cup. Doubtful animals should be tested by CMT. Repeated or severe cases should be reported to a veterinarian and milk samples should be sent for culture and antibiotic sensitivity testing.
Regular diagnosis, clean milking and proper record keeping are the main tools for mastitis control at farm level.
Conclusion
Mastitis is a major disease of dairy animals and causes heavy economic loss to farmers. Early diagnosis is the most effective way to reduce its impact. Farm-level methods such as animal observation, udder examination, milk examination, strip cup test and California Mastitis Test are simple and useful. Laboratory tests such as somatic cell count, milk culture and antibiotic sensitivity testing help in confirmation and correct treatment.
Mastitis control should not depend only on treatment. Regular screening, clean milking practices, proper milk sample collection, veterinary guidance and record keeping are equally important. Early detection protects udder health, improves milk quality and increases dairy farm profitability.
References
Merck Veterinary Manual. Mastitis in Cattle. Merck & Co., Inc.
National Mastitis Council. Laboratory Handbook on Bovine Mastitis.
Radostits, O. M., Gay, C. C., Hinchcliff, K. W. and Constable, P. D. Veterinary Medicine: A Textbook of the Diseases of Cattle, Horses, Sheep, Pigs and Goats.
Ruegg, P. L. A. A 100-Year Review: Mastitis detection, management and prevention.
Sharma, N., Singh, N. K. and Bhadwal, M. S. Relationship of somatic cell count and mastitis: An overview.
