Herd Test Results


You have the data from your first herd test but what do you do with it?  

Don't be tempted to go straight to the high-somatic-cell-count-cow section.  Start at the top of the somatic cell count (SCC) summary page (part 3).

Under each test date, two columns show the numbers and percentage of cows in each SCC category.  Focus on the top and bottom lines; cell count ranges 0-149 and 500+.  This tells you the amount of “clean” cows (<150) and “really dirty” cows (>500) at each herd test.  “Clean” cows should comprise >85% of the herd at the first herd test and >70% at the last herd test of each season. 

“Really dirty” cows should be less than 5% at the first herd test and less than 7% at the last herd test.  Heifers come in cleaner than cows and their “clean” targets are therefore higher and “dirty” targets lower. 

Low numbers of “clean” cows and high number of “really dirty” cows at any stage of the lactation indicate mastitis issues are present.  E.g. 65% of cows in the 0-149 category at the first herd test may indicate poor dry cow protection, high levels of chronic infections, problems in the colostrum mob, high levels of heifer mastitis and environmental contamination around calving, amongst other things.

The “likely infection rate” box tells you the likely number of infections at the most recent and the previous herd test.  By looking at the differences between tests you can see how fast infection is spreading or clearing in a herd. 

At the first herd test, this acts as a rough estimate on the efficacy of your dry cow and the effectiveness of early season management.  At the second and subsequent herd tests, this indicates how well infection spread is controlled in the herd.

Then look at the bottom section where individual high SCC cows are listed.
Remember: “not all high cows are problem cows and not all problem cows are high cows”.  For a cow to make it to your potential problem cow list, she must have been on the high list more than once or had repeated clinical mastitis. 

You might want to treat some cows to reduce the BMSCC.  Before treating any cows, ensure that they are still high (i.e. have not self-cured since the test) by using the RMT paddle to look for gelling and sub-clinical infection.  A weak reaction in only one quarter means reassess her in a few days.  She may self-cure.  Consider treating quarters with strong reactions to the RMT.  Extended courses of your recommended antibiotics work best.  Discuss treatment selection and WHPs with your vet.

However treatment of subclinical cows is often frustrating and poorly effective.  Running a separate repeat high SCC mob is effective in reducing spread of infection from high SCC cows to the rest of the herd.  All cows can be milked into the vat when BMSCC allows and when BMSCC is high the culprits are in a handy mob to quickly withdraw from supply. Small numbers can be run with the herd, being cut out at milking and run back into the shed to be milked last.

If BMSCC or clinical mastitis problems continue to plague you, please contact your nearest clinic.  We offer a range of effective solutions to resolve mastitis up to and including a full referral level package.