Can't see myself gathering my cattle, drawing blood, waiting for results, then getting the cows back in and sorting the dry's off for sale. Makes zero sense for this operation.
Here the vet comes, cattle are preg checked, dry cows and culls go one way out of the chute, breds another direction. Next morning the dry / cull cows get on a truck.
Preg testing is the only time a vet ever comes out, so is a good opportunity to have him look at different things and to maintain that vet / client relationship that is becoming ever so necessary.