Instructions
Introduce the horse to the harness. Allow him to sniff it and drape it over the various parts of his body, praising him the entire time he stands still and is accepting. Introduce him to the shafts at this time as well. Touch the harness and shafts to every part of the horse's body.
Buckle the harness on the horse and walk him around in it. Then, lunge him with the harness on so he can become accustomed to the feel of it at all gaits. Attach the shafts after you have lunged your horse and allow him to feel the way they are attached to the harness and where they will go on his body.
Have a second person follow behind the horse, holding the shafts as they are attached to the harness, as you lead the horse. If possible, have the horse trot with the shafts on. Have the horse drag the shafts behind him once he seems used to them so he can get used to the sounds and feel of them on the ground as well.
Introduce the horse to the cart by allowing him to smell it. Wheel it around him and praise him once he has investigated it thoroughly. Follow him with it as he is led around with the shafts trailing behind on the ground. The idea is to get him as used to the cart before you attach it as you did with the shafts.
In a secure location, such as an arena or round pen, attach your cart to the shafts and lead your horse around with the cart following behind. If you have done your job well, the horse should accept this all very readily. Take your time and make absolutely certain the horse is comfortable with the cart before you get into it. Lunging the horse with the cart at a walk and trot if you have enough lunge line and room in the pen.
Get in the cart for your first ride. Have someone lead him around the first few times. It may be a bit odd for your horse as he will be feeling the pull of your weight for the first time, but if you are patient and use your voice to praise him, he will soon relax and realize what he is doing is very akin to his saddle work.
If possible, take a well-broken cart horse along with you on your first trip out of the ring. Much like ponying race horses, having a green cart horse train alongside an experienced one can make things easier and safer.
How to Break a Horse to Harness
Having a horse trained to harness can increase the value of the horse, as well as introduce horse owners to a whole new level of enjoyment with their equine. Training a horse to harness is not difficult once a horse has been trained to ride.