There's generally an inverse relationship between contagiousness and deadlines. By the time it mutates enough to spread between people, it's unlikely it'll be much worse than COVID.
The thing is, in this case you can get infected from ingesting cow milk from a cow that was infected. Once it gets into our food supply it can cause something like a flu bomb that's going to kill a lot of people at once.
Vegans might have a better chance of surviving in this case.
But if we test, then maybe we'd have to not produce milk from positive cows for a short amount of time. Then someone might find it a little bit difficult to get milk for their morning cereal, and that would be a minor inconvenience.