Store these items in the trailer so you always have them on board!
Equine First aid kit
Spare Tire/Jack/Tire Iron
Three emergency triangles/flares
Wheel Chocks
Flashlight with spare batteries
Electrical tape and duct tape
Knife for cutting ropes in emergency.
Water - 5 - 20 gallons. Enough for drinking, cooling the horse if overheated, or washing of wounds in the event of injury.
Buckets/sponge
Spare halter and lead rope
Spare light bulbs
Spare fuses if applicable
Fire extinguisher
WD-40
Broom, shovel, fork, manure disposal bags
Insect spray