I also carry the following kit in my vehicle whenever I go on any kind of a trip or know I'm going to be doing something pretty dangerous around the ranch. It has items to care for both people and horses/cattle. The truck also has a store bought kit that stays in it year round. I figure the temperature extremes wouldn't be good on this bigger kit to leave it in the vehicle year round.

First aid kit for truck

Front pocket
-thermometer
-disposable scalpels (6)
-large heavy plastic straw
-rubber tournaquiet
-surgical scissors
-hemostat
-surgical tweezers
-curved surgical tweezers
-space blanket
-butane lighter
-dryer lint

Main pocket
-wilderness athlete hydrate & recover powder
-aleve (large bottle)
-Ace bandage + 4 safety pins
-Gauze pads (3”x3” quantity 10)
-gauze sponges (4x4 quantity 4)
-first aid & wilderness survival mini-book
-Benzalkonium antiseptic towlettes (quantity 9)
-Iodine prep pads medium (quantity 4)
-alcohol prep pads medium (quantity 2)
-athletic tape (3 rolls one 1” and two 2”)
-Iodine water tablets ( 1 bottle up to 25qts)
-Needle & 15ft of 10lb fishing line
-Wrap 1 roll self adhesive bandage
-Amoxycillian 1 bottle 19 capsules)
-bandages (standard and butterfly assorted sizes)
-calf suture kit
-corona ointment
-20 rubber gloves
-instant cold pack
-laxatives
-dental floss
-theraflu cold strips
-first aid quick guide book
-q-tips (8)
-2 tampons (gunshot or other major puncture wounds)
-hydrogen peroxide 4oz
-syringe wound irrigation (quantity 2)
-saline solution for wound irrigation (1 bottle)
-surgical scrub brush
-vetbond wound sealer (like superglue)
-Vetwrap 1 roll
-latex gloves (quantity 12)
-corona ointment
-coldpack (single use)
-quickclot (2 of a 3.5”x3.5” pad)
-horse first aid book
-antihistimine (benedryl)
-immodium
-tinactin (antifungal)
-carmex