News & Advice

Do you know your herd’s mastitis story?

Nov 6, 2019 | Dairy, Dairy Animal Health & Welfare

Jemma Guyton, Veterinarian, Anexa Vets

Are you frustrated because the antibiotics you are using aren’t clearing the clinical cases? 
Do you have a situation where even though your BTSCC is 250K you can’t find anything on the filter sock? 
Are you a herd that gets really sick cows with clinical mastitis? 
Do you enviously watch the neighbours go on OAD at Christmas time, but know you can’t because your BTSCC is too high? 

Knowing what kinds of bugs are causing mastitis in YOUR cows is crucial to making treatment recommendations and prioritising areas for improvement. Along with doing a Dairy Antibiogram (bulk milk mastitis resistance profile, see  for more information), taking milk samples for culture is a great way to build on the mastitis picture in your herd.

Milk cultures help to identify bugs that cause mastitis in individual cows, meaning you can tailor treatments for these animals. But more importantly, at the herd-level, milk cultures can help build a picture of what types of bugs i.e. contagious or environmental are most prevalent in your herd at specific times of the year. The more cultures you have, the easier it is to see a pattern i.e. Are you growing a lot of strep uberis? This is an environmental or ‘mud bug’ – are there muddy gateways that cause issues in spring and summer (with crop feeding)?

We recommend a minimum of 10 samples to get started! Collect sterile milk samples from high SCC cows at herd test, or pre-treatment from clinical cases throughout the season. You can freeze samples and submit them at your convenience to your local Anexa vet clinic (e.g. wait until you have 10 samples).

Then you can take advantage of our 10+ milk sample deal – when you submit 10 or more milk samples to the clinic for culture at our Anexa Morrinsville Lab, get 30% off.

For example: Recently a herd with an average cell count below 80,000 spiked up to 160,000 with an increase in clinical cases. Samples were taken from six cows with clinical mastitis (before being treated). Results returned a mixed bag of bugs including a couple of  coagulase negative staph  (CNS). Because there were only six samples and there was a mixture of bugs cultured we struggled to make clear recommendations at herd-level for the farmer. We did however, request that the farmer collect more samples. A further 15 samples were submitted 10 days later.

From this large group of cultures, it was easier to see a pattern in the types of bugs grown – predominantly contagious bugs, mainly CNS. It was determined with the growth of CNS that teat spraying was not up to scratch. CNS doesn’t often cause clinical mastitis, (it does push BTSCC up as in this herd), however it is a good indicator of how effective teat spraying is on farm, as CNS (which grows at the teat end) is easily killed with all teat spray active ingredients. After more investigating of this farm’s teat spray (product, preparation, storage, application and technique), the veterinarian determined that technique was great, but the type of teat spray was not suited to the farm. Since the change of teat spray clinical mastitis rate and SCC has decreased dramatically.

Moral of the story, more samples builds a better picture!

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