What is the main difference between test and remove and herd depopulation strategies?

• A. In test and remove, all animals are culled if any test is positive.
• B. In test and remove, only test-positive animals are removed from the herd.
• C. In herd depopulation, only negative animals are culled.
• D. In herd depopulation, vaccinated animals are automatically culled.

Answer: (B)

The key idea is how removal decisions are driven by testing. In a test and remove strategy, animals are tested for the disease, and only those that test positive are removed from the herd; the rest stay and continue to be managed. This contrasts with herd depopulation, where the plan is to culled the whole herd regardless of individual test results, aiming for rapid disease elimination. Therefore, the description that only test-positive animals are removed in test and remove is the best fit. The other statements misstate the approach: culling all animals if any test is positive isn’t how test and remove works; culling only negative animals contradicts the purpose of removing positives; and automatically culling vaccinated animals isn’t a defining feature of herd depopulation.