Why was the first day of a cattle drive often the largest and the hardest?

The first day of a cattle drive was often the largest and hardest because it involved the initial gathering and organizing of the cattle, which could be chaotic and stressful for both the animals and the cowboys. The cattle were often restless and needed to be moved from their grazing areas, requiring significant effort to ensure they were rounded up and kept in line. Additionally, the cowboys were still adjusting to the long hours and demanding physical labor ahead, making the first day particularly challenging. The excitement and adrenaline of starting the journey also contributed to the intensity of the day.