With the majority of cows now in milk, and hopefully over the tricky calving period, we can start to assess and deal with mastitis on another level. Up till now, the majority of infections will have been associated with environmental conditions, with Strep. uberis to the fore. In many herds, Staph. aureus will start to become more of an issue, particularly if the milking machine is not functioning efficiently, or there are “people” issues, such as inadequate teat spraying, over-milking or taking the cups off inappropriately. In the milkers, a reasonable target for new clinical mastitis cases would be 1% of herd size per month. So, anything more than 1 to 2 cases per week for a 500 cow herd should be considered significant. We can offer a lot of advice in this area, so please contact us to arrange a shed visit if you are concerned about the level of clinical mastitis, the size of the Bulk Milk Somatic Cell Count (BMSCC), or any other issues such as teat end damage.
Now is also the time to review your mastitis treatments, and get some samples in for testing. Some of the products you will have been using through the Spring may not be so effective against contagious bacteria such as Staph. aureus.
If everything is going smoothly, and the mastitis rate, BMSCC and incidence of teat end damage are low, then you can look to reduce the concentration of your teat spray (e.g. 1 part teat spray to 9 parts water for iodine based products, rather than 1:3 which you should have been using up till now).
With many farms herd testing around now, there is sometimes a need to raise the vacuum slightly for this procedure. I would avoid doing this unless absolutely necessary, and only make slight adjustments (1 to 2 kPa), taking careful note of the starting level. Above all, remember to turn it back after herd testing. Beware of faulty or sticking vacuum gauges, and if in doubt, get the vacuum checked after you have made the adjustments. Differences of 0.5 to 1 kPa can make a huge difference in some sheds.
Written by Jason Darwen BVSc
Extract from the Dairy Newsletter – October 2008
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