Farm Ireland

Wednesday 22 November 2017

How to avoid a mastitis meltdown on your farm

The expansion of the national dairy herd has seen a rise in mastitis outbreaks in low cell count herds

Make sure the parlour is fully serviced before resuming milking in a spring-calving herd
Make sure the parlour is fully serviced before resuming milking in a spring-calving herd

Don Crowley

When we speak about mastitis, we automatically think of high somatic cell count cows and elevated bulk tank SCC.

This type of scenario is often associated with the Staph aureus bacterium that causes an infection that lies out of sight in the udder resulting in a high cell count but no visible clots.

As Bulk SCC improves the incidence of this contagious mastitis Staph aureus reduces as infection rate drops.

After this busy spring, we are seeing in certain co-ops over 70pc of suppliers with BULK SCC of 200,000.

This is an excellent achievement when you consider the expansion occurring in the national herd.

Yet recently I received a call seeking urgent help to deal with an outbreak of mastitis in a low SCC herd - it stood out as this herd was consistently under 100,000 SCC.

With this drop in SCC other challenges can raise their head, one type of mastitis which is becoming more prevalent in spring calving herds is Strep uberus mastitis that doesn't result in elevated SCC.

It now accounts for more than half the callouts that I'm doing to farms with urgent problems. As the cell count in herds improves, you'd expect that this wouldn't happen.

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However, this bug is now getting more dominant and as herds improve this is the type of infection that farmers will now be facing.

This mastitis is mainly in the environment but has a contagious nature - it can be passed from cow to cow via milking liners.

It is something that can escalate suddenly and the herd received a sudden outbreak of severe clinical mastitis resulting in very sick cows, elevated temperature, swollen quarters and all requiring veterinary intervention.

It can be very aggressive and lead to very sick cows if missed over 12 hours, and it's a dairy farmers nightmare as it typically will infect your best milking lowest SCC cows.

You need to act on it very swiftly. The other Staph aureus mastitis was more of a slow burner and it built up over months with cell counts slowly rising. However, this new bacteria can takeover in the space of a week.

In a lot of these scenarios they can get clinical mastitis and still maintain a good cell count in the tank. They're looking good but suffering in silence.

Immediately, in this case we took culture samples from the 130 cow herd that showed Strep uberus was present and we stepped in to troubleshoot to assess any possible causes.

We worked with the milking technician and vet to remedy the faults identified and establish the best treatment.


The cleanliness procedure for milking was pre-spay and dry wipe, attach cluster and post spray after milking with a ready to use teat dip.

However, on investigation the teat condition was very good, but there was evidence of teat end damage.

This type of damage is caused by one or a combination of the following - excessive vacuum, faulty pulsation, over milking and removing clusters under vacuum.

During milking we established there was an issue with automatic cluster removers and an issue with the operating vacuum of the machine.

The cluster removers were removing clusters under vacuum damaging the teat ends and the operating vacuum was 51kpa, this should ideally be 46 to 48kpa.

These issues resulted in trauma over time to the teat ends, which compromised the cows own defence system and enabled an outbreak of Strep uberus mastitis in the herd.

The infection was then picked up from the cubicles as cows had access to them after milking prior to moving to pasture. A significant number would lie down on the cubicles after milking where the teat ends came in contact with the bacteria.

One of the most important things is to make sure that the parlour is fully serviced before resuming milking in a spring-calving herd. Also, many farmers cut back on milk recording due to financial constraints but this is a vital tool in helping detect issues. Ideally, the first milk recording samples should be taken before the middle of March.

Don Crowley is a Teagasc dairy advisor based in Clonakilty, Co Cork

Actions taken to deal with mastitis outbreak

The automatic cluster removers were corrected to proper flow rates, a delay time of three seconds between cut off of vacuum and engagement of string was enacted. The operating vacuum was dropped to 47kpa and cows were locked off cubicles pre and post milking during the grazing season.

Cluster dipping in a peracetic acid solution was started for a period of two weeks, solution was changed after every 10 dips, this was to help stop spread of infection.

A barrier dip was used post milking for a month until infection came under control. At drying off an internal teat sealer will be used in conjunction with dry cow therapy.

Following these changes there was a drop in the incidence rate within a week and after three weeks there were no new cases of mastitis.

It did impact on the milk yield of the cows it infected; these cows will not reach their potential this lactation.

This is a very stressful scenario on both the farmer and on the milking cow and can result in significant financial and physiological cost. Early detection is crucial and a plan must be put in place as soon as possible.

Mastitis prevention checklists

Areas to prioratise during summer months

* Lock cows off cubicles

* Milk problem cows last or disinfect clusters post milking

* Maintain post milking teat spraying with fly repellent

* Early detection is crucial

* Make sure vacuum clock is working and visible from the pit

* Change liners after 2,000 milking’s

* Wear gloves

* Monitor teat ends of cows for evidence of hyperkeratosis  (teat end damage)

* Milk record

TBC issues to watch for

* With elevated outside temperatures, ensure adequate hot washing

* Wash diversion lines after every milking irrespective if used or not

* Make sure dump buckets are clean

* Check dilution rates and expiry date of chemical

* Have a set routine, stick to it

* Inspect bulk tank after every collection

* Check temp of hot wash, over 70C

TCM (trichloromethane) / Chlorates

* Ensure adequate rinse water — 14 litres per unit

* Ensure proper dilution rate

* Do not store chemical outside under sun light, store in a dark cool area

* Avoid bulk buying, do not buy chemical for more than three months

These are some of the recommendations Dr David Gleeson Moorepark has highlighted from his work. There will be more detailed discussion at the Moorepark Dairy Open day on Tuesday July 4

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