According to The Cowboy Way, by David McCumber, about a cattle ranch in Montana, cowboys are riding around in their trucks and unloading hay for their cattle at this time of year. They are also checking on the health of the cows and innoculating those that have nasty diseases like scours, runny eyes, and pneumonia. They are also tinkering with machines, and one big chore is to check the "drop." That is checking the cows to see how close they are to calving.