well...one thing you could possible look into is artificial insemination, either the people you bought the does from or the ones that have the buck could possible know how to do it and could help you and since you have 3 does you could have the buck get all 3 in heat while they are separated but only let him do his duty on 1 or 2 and the others could be AI...always something to look into or contact your local vet, if its a large animal vet they should be able to help you with that and if not should be able to point you in the right direction. im mentioning this because the only buck available to you is black and white but you didnt mention how the dairy characteristics in his line are...with AI you pretty have have unlimited color and characteristics available its one of the easiest ways to make your herd better without spending oddles of money