Franklin Vets Blog

Early Season Milk Quality Results

May 18, 2020

Bulk tank somatic cell count (BTSCC) means different things to different people. For some, they just want to be under 400,000 so they can remain in supply. For others, they want to be as low as possible, have lower mastitis rates, receive bonus incentives from their supplier. For many, a low BTSCC is just something to be proud of achieving.

What many do not realise is that high BTSCC herds (>300,000) could gain a 2% increase in production by halving their SCC (or $42 for an average NZ cow at a $5.50 payout). This isn’t even taking into account things like reduced mastitis treatments, so there is a real upside to working towards a lower BTSCC.

Many farmers have spent time battling with their BTSCC, trying to achieve a better result by stripping, paddle testing or using their herd test data to identify the animals they think are the problem.

When the herd test results land in your inbox it is easy to just look at the millionaires and put a black mark against their number, but in the long run, is this going to change the SCC picture on-farm? In a lot of cases, the answer to this is no. BTSCC and mastitis are complicated with multiple factors coming together to affect the overall picture.

In the example below, a client had been struggling with end of season grading for a number of years. High infection rates in the mid to late season was limiting once a day options and days in milk, with problem animals being dried off early.

If you look at the blue line on the graph below, BTSCC rises throughout the season. 15% of this rise may be due to the decrease in volume, but this degree of elevation is suggestive of infectious spread within the herd. This was supported by the types of bacteria that were cultured from mastitis milk samples.

Bulk Somatic Cell Count Graph

With all mastitis bugs we have two main ways of tackling them:

  1. Prevent them from infecting cows
  2. Using antibiotics to cure infections when inside a cow.

Our main focus should always be to prevent animals from becoming infected; this can be achieved by ensuring that the milking machine and milking practices are operating well, optimal teat spray application and that cows which are infected have limited opportunity to infect their herd mates.
Antibiotics (particularly dry cow) have been a major way of curing infections. Unfortunately, there are a couple of issues with relying heavily on this strategy; 1) antibiotic use is becoming more restricted and 2) In certain bugs, treatment is often not effective. So, our main control of these mastitis bugs is to remove the infected animal from the herd for the protection of the other animals.

In this scenario, a number of alterations to the shed were made to improve teat-end condition, such as installing lighter cups so the vacuum could be dropped.

In the client’s opinion the biggest effect was moving away from looking at the millionaires and digging a bit deeper to find the chronically infected animals which rolled from season to season, who’s SCC didn’t respond to dry cow. If dry cow isn’t going to cure an infection, it is unlikely we can cure them. So, we need to manage them in a way which protects the rest of the herd.

With a lot of hard work, focus and targeted culling, the bulk tank dropped a significant amount the following seasons, see graph above (Red line).

Tackling SCC in herds is complicated and is often not a quick fix. By looking at your data and the clinical picture on farm, we can make a strategy moving forward.

There are a number of service available through Franklin Vets which you have access to which might help tackle these situations.

  • Sitting down with your vet for an early season milk quality review (ESMQR) to find problem cows. You can review the early season SCC trends in the cows and heifers, allowing identification of problems and early intervention
  • We have Fonterra accredited mastitis experts within the practice who can perform a milk quality visits to help optimise milking practices and carry out grade busts
  • There are also a variety of new testing options available which might help shed some light on the situation on your farm.

Dr David Moors BVSc (Dist) BSc (Hons) MANZCVS Medicine of Dairy Cattle