I have heard some Christians say that the purpose of animals, and their destiny, is to be of use to mankind, mainly to be killed and eaten. I wonder what Bible they read, and what forms of worship they use.
From a Biblical perspective the concept of eating anything but plants by any animal - human or otherwise - only entered the world after The Fall. That surely should tell the reader something.
Two Canticles in the Daily Office concentrated my attention further. The first was the Benedicite , a canticle used on joyous occasions in both Anglican and Roman Morning Prayer. It clearly reminds us that the purpose of all creation is to praise God. Animate and inanimate, animals and humans are all called to praise their Creator. That is their purpose and destiny. I quote but one verse:
And you, rivers and seas, O bless the Lord. And you, creatures of the sea, O bless the Lord. And you, every bird in the sky, O bless the Lord. And you, wild beasts and tame, O bless the Lord. To him be highest glory and praise for ever.
Note: not for humans to praise God for giving them these creatures to eat (which He hasn’t), but for the creatures themselves to praise God. To be able to do this they must live as God intended, above all they must be alive, a fact of which we are reminded in another Canticle, “A Prayer of King Hezekiah in his Illness”.  I quote just two verses: 
No one in the world of the dead can praise you; The dead cannot trust in your faithfulness. It is the living who praise you, As I praise you now.
It is worth reminding our fellow Christians of this, and that our present predicament - along with HIV/Aids, SARS and many others - comes from the killing and eating of animals. Whoever wrote these passages - along with others such as Genesis 1  and the vision in Isaiah 11  knew what they were talking about. Our present situation I believe is proof of their Divine inspiration. These passages are part of Holy Writ which every Christian should know, and not ignore or try to explain away.
Footnotes: 1: taken from the Bible (Daniel 3:56-88)(Catholic version) or Apocrapha: A Prayer of Azariah (Protestant version) 2: Isaiah 38:1-20 3: vv18 & 19a 4: v29 "Behold, I have given you every plant yielding seed which is upon the face of all the earth, and every tree with seed in its fruit; you shall have them for food. 5: The wolf shall dwell with the lamb . . . They shall not hurt or destroy in all my holy mountain