Much progress has been made in recent years to improve clinical mastitis incidence, however we must not become complacent.
Although the dairy industry has reduced clinical mastitis massively from the days of in excess of 150 cases for every 100 cows a year to below 50 cases for every 100 cows in the 1980s, 2005 data showed an upward trend which is likely to have continued (see graph).
Sub-clinical mastitis levels – most commonly identified by somatic cell count (SCC) – have improved, mostly as a result of the introduction of the EU directive 92/46/EC which placed significant financial penalties on high SCC and a 400,000 cells a ml upper limit for saleable milk. However, bulk milk somatic cell counts appear to have plateaued at about 200,000 cells a ml.
Records play a crucial role in tackling mastitis. Paper records have their uses, but computer analysis makes for easier, quicker and more useful outputs.
Cell count records
Many dairy farmers have monthly individual cow SCC (ICSCC) records. In the past they were filed away in a drawer (still in their plastic bag) and never put to use for finding out what was happening at farm level. However, we have moved on.
Many farmers are now looking at their new infection rates or their dry period performance, as well as recognising that some cows are broken and have such a chronic long-term SCC problems that they will never get better. But this is only half the story.
Clinical mastitis records
All farmers recognise broken cows with clinical mastitis. These may be cases where the quarter is lost or the cow just keeps on getting mastitis again and again in that quarter. However, the use of accurate and complete clinical mastitis records with calving dates (easy with computerised records) can give insights into a herd diagnosis much as we have with ICSCC.
With clinical mastitis – when do most cows that get mastitis first enter the mastitis cycle? When is the “index” or first case in a lactation in your herd? Of course this may not always be simple because some cows carry an infection right through the dry period so you need to integrate ICSCC data to get the best handle of what is happening.
Imagine a bath with the plug out and a crack in it. If you want a bath, you best put the plug in the hole before you rush to find that mastic gun. It is the same with mastitis and this is where your vet comes in. The whole picture needs looking at. There is no point in upgrading the parlour or fitting a cluster disinfecting system when most infections are being picked up in the dry period. You would be better spending that money on improving or enlarging the dry cow accommodation.
Talk to your vet and find out where your plug hole is and leave that mastic gun alone.
Recording mastitis rates
Records for clinical cases are predominantly used to avoid antibiotic failure, but they should be used to look at:
- New infection and repeat rates
- Pattern recognition
- Where is the infection mostly getting in – dry period or lactation?
- Where is infection coming from – other cows or the environment?
- Type of bacteria involved
- Clinical cases or high SCC cows – Gram +ve or Gram -ve, contagious or environmental