The cattleprod is a members-only quest item used only during the Sheep Herder quest. It is found near the incinerator. When wielded, players can "prod" the sick sheep with it, so the sheep move to the opposite direction where they were prodded, and move to the enclosure. Upon completion of Mourning's End Part I the sheep can no longer be prodded.
If lost, it can be re-obtained at May's Quest Caravan after putting 150 quest points into the Hub Track. It can also be re-obtained from the incinerator area if players kept their plague jacket and plague trousers from the Sheep Herder quest. If you try to enter without the plague set, the player will refuse to enter and says:
It doesn't look very safe in there. I'm not going in without decent protective clothing.
Alternatively, the cattleprod can be re-obtained by standing just right of the gate and using Telekinetic Grab on it.