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Important message from the TVMDL

September 3, 2016

Dear Texas Deer Breeder,
The following message is being forwarded on behalf of Texas A&M Veterinarian Medical Diagnostic Laboratory (TVMDL). Please read closely.
Due to recently received additional guidance from USDA on the protocol for processing  antemortem rectal biopsies, the number of samples deemed to have “insufficient follicles” has increased. The following guidelines are being suggested in an effort to increase the odds that a sample may contain sufficient lymphoid follicles (6 or more) and therefore allow for a valid test result.
  1. Size of rectal biopsy – It is suggested that the biopsy be no smaller than a dime and no larger than a quarter.
  2.  The number of deer sampled should include, on average, 20% more deer than the number of required “not detected” results.
  3. Age of deer – as animals age the number of lymphoid follicles decreases. This is a normal physiological ageing process. If deer in younger age classes (2-4 years old) are sampled then number of samples with insufficient follicles due to the ageing process is reduced. The older the deer, the more likely it is that the sample will not contain sufficient follicles for a valid test.  This may be partially offset by taking a larger sample i.e. quarter-sized rather than dime-sized.
If these factors are addressed then the chance of having a submission that will yield the necessary number of follicles required for valid test results will be increased, avoiding the need to resample and resubmit.
If you have questions, contact