Prevention of mastitis is our primary goal-if cows don’t get infected, then we don’t have to worry about how to cure them! Knowing which pathogens the herd is being challenged with, relating to both cases of clinical mastitis and cows with high SCC, can help to ensure that efforts at prevention are targeted correctly. We can do this easily by taking a sample of milk from a cow with mastitis (clinical or sub-clinical), and getting a laboratory to identify which bacteria are in the sample.
Milk sample plate with bacterial growth
Once the laboratory has grown the bacteria, they can also check if they are resistant or sensitive to a predetermined list of antibiotics (‘sensitivity testing’). While this does not guarantee that an infected cow will be cured by a particular antibiotic, as conditions on a laboratory plate can differ dramatically from conditions in the udder, it is important to be aware of any resistance issues that may be emerging on farm and to choose a treatment that should be effective.
Antimicrobial sensitivity plate
To get good results……take good samples, and use a laboratory that has a proven performance record i.e. a CellCheck Partner Laboratory.
- Taking good samples:
Hygiene is essential-whichever bacteria you collect in the sample of milk, whether they come from the quarter or from the environment, will be identified y the laboratory. Mixed bacterial infections can occur in mastitis, but when three or more different bacteria are identified in one sample, this is universally recognized as evidence of a contaminated sample.
Taking a sterile milk sample
For step-by-step instructions on taking and handling milk samples in a sterile fashion, see Management Note A in the CellCheck Farm Guidelines for Mastitis Control.
- CellCheck Partner Labs:
CellCheck has been working in partnership with the Department of Agriculture, Food and Marine to harmonize methods and standards of commercial services available for mastitic milk samples. Limerick Regional Veterinary Laboratory (RVL) has developed a proficiency test (PT) scheme, which all commercial laboratories offering milk culture/PCR services are welcome to participate in. Phase 1 of the PT scheme focused on bacterial identification, and provides participating laboratories with an opportunity to evaluate their methods and results on a quarterly basis, and score their performance. Phase 2 of the PT scheme will look at standards of sensitivity testing services on offer. Participating laboratories also contribute results from commercial samples received into a central, anonymized database, which means that there is a more comprehensive understanding of the pathogens causing mastitis in Irish herds, and any related antimicrobial resistance patterns.
Any commercial laboratory that successfully participates in the DAFM PT scheme is recognised as a ‘CellCheck Partner Lab’, delivering mastitic milk sample services to an agreed standard and undergoing continual evaluation in this area.
The current list of CellCheck Partner Labs is as follows – Click here