I'm glad Commander-in-chief Biden is the man in the Oval.

Cows don't get a lot of contact with birds. Unless American dairy corporations have greatly changed how they care for cows.

Birds do hang out in barns where cows hang out but then a lot of livestock does too. Horses, sheep, goat, pigs, they all have exposure to large barns.

Why Dairy cattle?

Pigs, I could understand. They'll kill and eat chickens and other birds without a problem. But cows?

Any predator, like a dog or a cat perhaps, could easily be exposed through hunting and eating birds.

Something is weird about cows spreading it. The cows can even spread it between themselves. And then it moves to the mammary glands, to show up in milk. It usually stays in the respiratory system.

I wonder if they will find it in cows and milk in other countries?

and I remember when it hit hard here in PA, even the zoos reacted by not only bringing their birds inside some enclosed area, but by carefully dealing with both vehicle and foot traffic into and out of the zoo area to keep from "tracking" any pathogen near where the animals were domiciled (knowing that wild birds were already flying around as well).

So perhaps something introduced (as external droppings) via the feed or even the water.