Tripods aren't necessary, although a monopod might come in handy. You'll probably get best results shooting handheld. A medium range zoom lens is best for action shots, although there is opportunity for other unique shots as well (barn activity, people, dogs). There are two outdoor show rings and several barns. Horse shows usually go rain or shine.
We would like to make images available to the competitors to download for their personal use, mostly for sharing on social media.