BVD antibody (milk)

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Interpretation of Bulk Milk Antibody Results for BVD
The test result is presented as a percentage positivity with a score to aid interpretation. A single sample is a snap shot in time and a series of monthly or 3 monthly samples provides better evidence of the dynamics of the disease in the herd. The status of animals not contributing to the bulk tank is not assessed e.g. youngstock, dry cows, sick cows, bulls. The vaccination history of the herd should be taken into consideration when interpreting these results as in some cases vaccination will result in positive values.

The score should be interpreted as follows when considering a bulk milk sample result:

Score 0 - Very Low/ Undetectable antibody levels (Percentage positivity </= 2%)
This means that herd exposure to BVDV is unlikely. Reviewing herd biosecurity and routine bulk tank monitoring is recommended.

Score 1 - Low antibody levels (Percentage positivity >2% to <14%)
Only a small proportion of the cows may have been exposed to BVDV. Reviewing herd biosecurity and routine monitoring of bulk tank is recommended.

Score 2 - Intermediate antibody levels (Percentage positivity >/= 14% to </= 29%)
Herd exposure has occurred at some time, but there is unlikely to be a viraemic cow present in the herd. A composite sample from first lactation animals is recommended as the next step to monitor the herd status. If this too is positive then screening of the bulk tank for BVD virus by PCR is recommended.

Score 3 - High antibody levels (Percentage positivity >/= 30%)
The herd has a large proportion of exposed cows. A composite sample from first lactation animals is recommended as the next step to monitor the herd status. If this too is positive then screening of the bulk tank for BVD virus by PCR is recommended.