My uncle used a male vet who has been preg checking for the family for decades, and who arms (reaches in and uses his hand to physically feel for the calf) instead of ultrasounding. He and my aunt set up a temporary corral in a hay yard, and the vet brought his own hydraulic chute.
Here is the vet's table at my uncles, complete with paint for marking opens, lube, a syringe since he was giving one shot and his hotshot to provide encouragement as needed.
At my uncles, the open heifers were given a big, "O" in the middle of their back with white paint that will not come off of anything....anything!
Both days each bred heifer was poured to guard her against common parasites and flies, both internal and external.