How to Remove Burrs From Horses

Getting Rid of Burr Plants
Once youve cleaned all the burrs from your horse make sure you dispose of them where they wont sprout. Dumping them on the manure pile or sweeping them out the barn door might land you with a crop of burrs right next to
your barn. Dont put them in a composter either. Instead throw them in the garbage or burn them on your next bonfire.
To avoid having to pull burrs again youll need to 

 eradicate the weeds from your paddocks and pastures. The common burdock is a biennial. It grows leaves and roots its first year and it flowers and goes to seed in its second year before it dies.

There are two times when you can cut down burdock to stop its growth. Early in the spring use a sharp spade to chop the first leaves popping up at soil level. This should kill
the plant. But if the plant already has leaves cut it down just as it begins to flower. This way the plant thinks it has produced seeds and shouldnt grow again. If you cut down the plant before it flowers it will attempt to come back and flower the following year.
You can try chemical herbicides but these need to be used with great care in horse pastures. Horses typically must be kept away from any sprayed areas until the herbicide is dry.