A contract is a must and this must cover all the practical things that you can think of. Think hard and make a list including the obvious - basically you need to allocate responsibility for all the things that you do with your horse for granted. As to insurance, it is likely that the owners insurer will say that you need to take an insurance policy, or the owner needs to maintain theirs. It is usually not possible to have two seperate policies for one horse. The contract needs to make sure that the arrangement is a loan and not a sale and that title to the horse remains with the owner. It needs to deal with the period of the loan and what happens at the end. You should include termination rights so that either you or the owner can end the loan on the occurence of certain events. You might want to agree what notice period each shall give and also what happens on termination in relation to any outstanding costs. You may also want to consider limiting your liability under the contract so that in the unfortunate situation that you are sued for breach of contract or negligence you know the extent of your liability. You may want to shop around and see if there is some form of indemnity cover available that protects you if you are sued under the contract. Once you have put the agreement together read it or get someone else to criticise it and ask what happens if this happens etc. Hope this helps!