Mastitis can impact on a dairy farming business in many ways
The direct costs are well recognised and consist of:
  • Cost of labour
  • Discarded milk
  • Culling
  • Loss of heifer/cow (death)
  • Lowered milk quality payments
  • Decreased milk production
  • Cost of treatment.
But there are many other impacts of mastitis

Time – The time taken dealing with mastitis limits the time available to do other things properly.

The period of peak incidence of mastitis cases is also when farmers are dealing with calving cows, collecting calves, metabolic disease, post calving illness and diseases of the reproductive tract that can impact on the cows’ production as well as their ability to get back in calf.

Stress – With all that is going on, spring is a stressful time of the year anyway. Dealing with mastitis at this

Time, or an escalating Somatic Cell Count (SCC) count later in the year, can add further stress.

Staff – Dealing with a significant mastitis problem is difficult for staff, impacting on job satisfaction and adding pressure to the job. It is well documented that there is a very high turnover of staff on New Zealand dairy farms. It is likely that animal health issues such as mastitis play a part in this.

Animal welfare – The vast majority of farmers pride themselves on looking after their stock well. Mastitis can be an uncomfortable and often painful condition for cows. Reducing the occurrence of mastitis is undoubtedly in the best interest of the cows.

Calves – As well as limiting time to manage calves well, mastitis in the herd can reduce the quality of milk fed to calves.

Increased exposure to antibiotics (either before they are born or via milk from treated cows) and bacteria can occur.

Adding mastitis milk to colostrum fed calves dilutes it and reduces the ability to store the colostrum for future use.

Milk quality and market access – Dairy farmers are producing a food product. Quality product is important to satisfy the needs of customers with ever increasing expectations. This is reflected in an increased focus on SCC by New Zealand dairy companies of late.

Season length – SCCs increase towards the end of the season with declining production and the spread of contagious bacteria throughout the lactation. This can lead to having to dry off a significant proportion of the herd earlier than necessary.

Reduction of management options – Options such as once a day milking (in a feed pinch, for ease of management or to maintain cow condition) can be challenging in herds with a highcow condition) can be challenging in herds with a high SCC as this increases SCC further.

A somatic cell is basically any cell that is derived from a cow’s body.

The SCC that is reported either for bulk milk on the tanker docket or for individual cows with herd testing is a measurement of the number of ‘body cells’ in the milk.

Some of these cells are from the udder itself, particularly from the lining as they are continually being shed and renewed.

Most of the cells, however, are white blood cells – these are part of the cow’s defence mechanism and increase in number when the cow is fighting infection.

The white blood cells are the main constituents of pus – so most of the somatic cells seen in milk are, in fact, pus cells!

" For every clinical case of mastitis, there will be 15-40 subclinical cases. "
A somatic cell is a pus cell

Current SCC limits are 400,000 cells per millilitre
- that’s 2,000,000 pus cells per teaspoon.

The main driver of SCC is mastitis

When there is an infection in the udder the SCC increases as the cow tries to fight it off.

In some cases the cow’s reaction is severe enough that we see clots of debris in the milk and swelling of the udder – this is clinical mastitis.

However, most of the infections in a herd will not be able to be seen, they are called subclinical.

The main factors affecting Bulk Tank Somatic Cell Count (BTSCC) are:
  1. Mastitis
  2. Stage of lactation
  3. Cow’s age
  4. Udder trauma
  5. Management factors such as nutrition, teat spraying, Dry Cow Therapy (DCT), culling and mastitis problem handling.
Halving the Somatic Cell Count (SCC) (e.g. dropping SCC from 200,000 to 100,000 cells/mL) is estimated to yield almost 2% additional production.1

This is in line with overseas data estimating a production gain of between 1% and 3% for a drop in SCC of 100,000 cells/mL.

Not to mention the added benefits of...
  • Less clinical mastitis
  • Less stress
  • Less costs incurred
  • Less time lost.

Malcolm D (2006). The cost of mastitis study. Proceedings of the SAMM Milk Quality Conference.