It's a surplus tax, and one that apparently doesn't exist for the majority of dairy imports: https://archive.is/kKsYc
that tariff would only apply if we were able to reach and exceed the quota on U.S. dairy exports agreed to under the U.S.-Mexico-Canada Agreement (USMCA).
[...] the U.S. has never gotten close to exceeding our USMCA quotas
It's a surplus tax, and one that apparently doesn't exist for the majority of dairy imports: https://archive.is/kKsYc