The fourth and final phase is the Cattle Trial which tests the ability of a horse and rider to work cattle individually and with teammates. This is a team event: 3 to 4 riders work together to cut pre-selected cows from a herd one at a time in accordance with a pre-established order, and herd them into a holding pen separate from the rest of the herd. The objective is to demonstrate the abilities of cutting/ herding/containing cattle efficiently and accurately. A show may also offer a Cattle trial for individuals that runs in the same manner, awarding individual placings.
This is not offered at all competitions at this point in time.
Rules for the Cattle Trial can be found on Page 47 of the rulebook in the link below.