If you complete the process of creating a horse bill of sale correctly, you and the buyer will normally each receive a copy of the document after it has been signed.
However, if this has not happened, you should immediately contact the other party immediately and request a copy.
This is necessary to prove that the horse has legitimately changed ownership and that the sale was carried out correctly.
If you’re the buyer in this case and the bill of sale is never delivered, and the seller refuses to give you one, you should contact a lawyer and seek legal advice on the matter.