I am both Christian and Zoo. By his death and resurrection, Jesus did away with our debt of sin, and by that means the detailed requirements of the old Abrahamic laws, including the need for animal sacrifice (what did the priests do with the thousands of animal carcases every day??) to keep our souls pure before God. This does not mean we can go out and party hard, commit horrid crimes, think bad thoughts, but we have greater freedom along with greater responsibility for our actions. It's like the difference between primary school - lots of detailed school rules that are confusing and impossible to keep - and high school - the rules are still there, but make sense because we've grown a little bit and so give us more freedom and responsibility. In Mark 12:30-31, Jesus renders all the commandments and rules God gave Moses into two commands that both have the word "love". My interpretation of this rendering, that turns the hundreds of laws and regulations of the OT into a neat bundle, is to do whatever you choose to do with love. If you love in a Godly fashion your neighbour (translate as "everyone"), you will never do harm to anyone; ditto animals. So - here's my message. If you truly love your animal friends, even during sex, you will never harm them and so you are automatically doing what God wants of you.