Mid-lactational mastitis
At this time of year, an increase in the Bulk Tank Somatic Cell Count (BTSCC) may have alerted you to the need to look further into your mastitis management. This could be as a result of increased clinical or subclinical cases within the herd.
As the season progresses, the ‘contagious' mastitis bacteria, such as Staph aureus and Strep dysgalactiae, play a bigger part in the clinical mastitis picture of the herd. These bacteria are spread during milking. Staph aureus often shows some resistance to penicillin so use of another antibiotic at this time of year may be necessary. This is when it is very useful to submit milk samples for culture and sensitivity to antibiotics.
Early detection
As these bacteria are spread during milking, it is important to find those clinical cows and remove them from the herd as soon as possible. The Seasonal Approach to Managing Mastitis (SAMM) plan continues to provide very useful information on this. Look for swollen quarters, abnormal foremilk and clots on the filter. Any doubtful quarters can be checked using the RMT (Rapid Mastitis Test) or conductivity.
Subclinical cases generally begin to rise in mid-late lactation and are seen as a high BTSCC or grading problems. Subclinical cows, as the name suggests, will not show outward signs of mastitis so are difficult to pick up. In order to find these individual cows, a herd test or RMT of the herd, will need to be undertaken.
As for clinical cases, once these individual cows have been found they should be removed and treated. Totally Vets can provide a grade-busting service. This involves working through herd test data as well as a visit to the shed before and during milking to try and pinpoint problem areas.
Treatment
One of the fundamental principles set out in the SAMM plan is to reduce the duration of existing infections. As lactation progresses we have three realistic options:
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Treat with lactacting cow antibiotics
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Dry-off and treat with dry cow therapy
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Cull
The decisions that need to be made will be done on an individual animal basis and require information such as mastitis history, age, dry cow treatment history and production.
For those cows that have been repeat offenders and have not responded to lactating cow treatment, drying that animal off and giving her dry cow antibiotics could provide the best chance of clearing her up. For older cows with a repeat history despite multiple dry cow treatments, culling may be looked at more closely.
Milk samples
Later in the season as we start to think about dry cow therapy, it is very helpful to take milk samples from any clinical cases for culture and sensitivity. This information allows you know what bacteria we are dealing with and therefore get the most effective dry cow treatment for the job.
If you would like help investigating mid-lactational mastitis or want to avoid this year's problem spilling over into next season's production, contact either of the Totally Vets branches for a chat with a vet.
