Detecting mastitis
2 min read
Early detection of clinical mastitis is key to protecting milk quality and cow health. Check regularly for signs such as, heat, swelling, and pain in the udder, as well as changes in the milk, including wateriness, clots, or discolouration that continue beyond the first few squirts. These are clear indicators of clinical mastitis and require prompt treatment. This page outlines how to recognise these signs early and the appropriate actions to take.
Clinical cases of mastitis are costly to the business and disrupt the milking routine. If clinical cases are missed, they contribute high numbers of cells into the vat; this can significantly increase bulk milk somatic cell counts (BMSCC).
Early detection of clinical cases means cows can be treated appropriately to reduce pain and discomfort, resulting in fewer chronic infections, less chance of infection being passed to other cows and reduces the risk of milk quality grades. This requires staff to be aware of signs that indicate clinical infections and situations that increase the risk of mastitis spread.
| Severity | Milk | Udder | Cow |
| Mild | Abnormal | Normal | Normal |
| Moderate | Abnormal | Inflamed | Normal |
| Severe | Abnormal | ± inflamed | Sick |
Cases that require treatment are those where there is heat, swelling or signs of pain in the udder, or changes in the milk (wateriness, clots, discolouration) that persist for more than three squirts of milk. Not all cases will require antibiotics, so it is important to avoid using antibiotics on cases that may otherwise clear up on their own. Consult your veterinarian regarding treatment plans.


More information on detection and signs to look for in our healthy udder guide.
High numbers of clinical cases may indicate problems with preventing mastitis before calving and in lactation, missing cases in the colostrum period or treating cases that did not meet the definition of a case requiring treatment.
Trigger for action: 10 cases per 100 mixed-aged cows calved, or 15 cases per 100 heifers calved, based on farmer diagnosis of clinical mastitis within 14 days of calving.
For further information, discuss Technote 4 with your vet.
When you have an immediate issue, follow these steps to isolate and treat the affected animals.
Strip herd to find missed clinicals.
Identify high SCC cows. Arrange emergency herd test or check herd with an RMT (Rapid Mastitis Test)
Milk sample for culture - helps identify what bacteria you are dealing with and how to treat it.
Get help from professionals to spot problems with your systems.
For more information, visit our treating mastitis page.
Make sure only true clinical cases are being treated, and that protocols are being followed correctly. Consult your veterinarian for advice if a clinical quarter fails to respond by the end of a full course of treatment.
To prevent future issues and improve overall farm performance, take a strategic look at your management systems.
Start by understanding what mastitis is costing your farm and where the biggest losses are, using tools like the Mastitis performance calculator and your Mastitis Focus Report to pinpoint when and where issues are occurring.
Review how well your prevention, detection and treatment systems are working, particularly around the colostrum period, where poor detection can lead to more clinical cases later in the season.
If problems persist, bring in a second set of eyes such as your vet, milk quality advisor, or consultants like AsureQuality or QCONZ to help identify gaps and improve your overall mastitis management.
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