Strangely, Rainboy, I have had to think quite a bit about this topic. I'm in correspondence occasionally with someone who, as much as it is reasonable to believe based on internet contact, seems genuinely to be a 13 yo fellow who is registered at a BL site. This gentleman has a boyfriend a few doors away and other than that leads a very quiet life. Of the 3 people he chats with regularly, one became very alarmed at one point and told me that that the young man had begun to have sex regularly with his dog. And was defending this practice vehemently with citations from zoophile sites (including some that, when I was passed on the links, I found did indeed have some photos.)

I treated this as unsubstantiated (even when another mutual friend later made a similar claim about the young man), but I did make sure the young man had an opening so that if he ever wanted to discuss this with me, he could. He never has and the issue has died down; he now speaks very little to the two with whom he allegedly discussed the dog business. But I did have to imagine what I would say to him if he ever raised the topic with me.

This thinking process hasn't changed my basic position, which is that animals have a sexuality of their own that (in the species we're dealing with here) consists of females coming into heat and pairs copulating only at that time in an instinctive way that doesn't involve any sort of ongoing couple-type partnerships (though in the wild, stallions will defend a group of mares until a more vigorous stallion drives them off.). I think it would be best if that sexuality were respected and that of another species not imposed upon the animals.

What people may do when they imagine dogs or herbivores are their romantic partners is very tangential to the sexuality of the animals. However, farmers have long masturbated bulls to get semen for sale, and doing the same for kicks alone doesn't seem to be remarkably worse in terms of biological ethics.

The animals, which at best approximate the mental age of a human 18 month-old, certainly can't give knowledgeable consent in any way the term is normally used, though I am certain that their romancers would say they can at least play along.

Setting aside Christianity and looking at it from the secular point of view, it would seem to be disturbingly exploitative and yet, if the animal's enthusiasm were demonstrated, perhaps to be tolerated, at least by people who can also tolerate pedophiles.

Putting Christianity back in, I think the Mosaic law with all that stuff about two kinds of thread and one crop per field and selected kosher animals is, in essence, a ringing call to God's people to a kind of purity or "nazirite" existence (less stringent than that of avowed Jewish nazirites) where they really made the best of what God had given them. And didn't get sidetracked on all sorts of miscellaneous feeding frenzies as the Canaanites had. Out of the whole smear of things that could be represented as love, including affairs with one's relatives or one's wife's mother, dalliances with animals, liaisons with prostitutes or multiple spouses or diverse extramarital partners, I think that we are called upon to pull out the very few superior possibilities that maximize our ability to manifest God's love here in our relationships on this earth. The sayings of Jesus and of St. Paul only serve to amplify that impression.

Now, at this point, Rainboy we split into two different political parties, or at least that's how it strikes me at the moment. One party would recommend that I, as a representative of a type called "man," ought to maximize my loving potential before God by marrying another type called "woman" and undergoing, if possible, the miracle of reproduction with her.
If I am not capable of doing that, it may be that my sexual orientation is a type of handicap and I should resign from the possibility of sexual love. The other party would recommend that I see the typological statements in the bible (like "God MADE THEM MALE AND FEMALE. FOR THIS REASON A MAN SHALL LEAVE HIS FATHER AND MOTHER, AND THE TWO SHALL BECOME ONE FLESH) as just referring to the typical case where the prescription would actually work in reality, and then, transposing the basic principles to my own situation, that I should maximize my loving potential before God by finding the equivalent help-meet, whose loving potential would also thereby become fully realized, and become one flesh with him.

This discussion is not one I'll come back to elsewhere. The important thing here is that though someone could perhaps claim that they are maximizing their loving potential before God by taking up on their most loving, enduring, tolerant sexual strain as being directed towards animals, first of all, I find it hard to believe this is true; but supposing it were, even then, I can't see the reverse argument, that this process would also allow the animal to reciprocate. The animal is an animal doing animal things, not a human consecrating himself to God's love.

Men who are not homosexual are well known, for example in prison, for using other men for sex; horny farmboys are famous for using animals likewise. My interpretation of scripture is that God is not pleased with this transformation of consecrated loving potential to temporary exploitative usage. The motivation of a homosexual male who has sex with a woman to fulfill family obligations and keep on the good side of society is exactly the same as this type of usage, so I don't distinguish these cases. Certianly in the case where animals are just being used as surrogates, you can rule out these liaisons as holy.

Even in cases, though, where people may claim the animals are being honored and loved as their primary partners, the animals are not cognizant of any of this -- perhaps people could also train one-year old babies to lick in all the right places and say ooh and aah when their genitals were stimulated. To me this is still a sort of usage. It is not a real primary partnership in the eyes of God.