The Bible says we have "dominion" over animals, so why shouldn't we eat them? This is a very complex question, about which much can be said. Entire books have been written on the subject. Let's break it down into a few key points to consider.
1. What does "dominion" mean?
Dominion is a word that we don't usually use in everyday conversation. So what does it mean? "Dominion" doesn’t mean "exploitation", "decapitation", "torture", or "domination", but rather a responsibility for stewardship.
Dominion is a responsibility, not a gift.
Some English versions of the Bible translate Genesis 3:16, describing womankind's pain in childbirth and relationship to man using the word "dominion" as well, but no one is advocating that this is a reason to treat women in the same way we treat animals. The concept of dominion over animals as a reason to eat them, then, is really being used as an excuse or a justification, rather than a valid Biblical interpretation.
The exact wording is different in different translations and versions, but the concept is the same. For example, here's the New International version of Genesis 3:16:
To the woman he said, "I will make your pains in childbearing very severe; with painful labor you will give birth to children. Your desire will be for your husband, and he will rule over you.
Here's the Catholic Douay-Rheims version:
To the woman also he said: I will multiply thy sorrows, and thy conceptions: in sorrow shalt thou bring forth children, and thou shalt be under thy husband's power, and he shall have dominion over thee.
2. Mercy and compassion are fundamental Christian values.
All the world’s prominent religions, including Christianity, teach the importance of both compassion and mercy as important values to cultivate.
However, the choice to eat meat, dairy products, and eggs is always a violent one—it inarguably supports abuse and unnecessary killing of sentient beings.
We're lucky enough to live in a world with a variety of egg substitutes, dairy substitutes, and even meat substitutes readily available, meaning that eating animals is absolutely, inarguably unnecessary for people living in developed nations.
The only merciful and compassionate choice when considering choosing between killing sentient beings or not killing sentient beings is quite clearly the one which does not cause unnecessary pain and suffering. Christians who want to cultivate mercy and compassion in themselves should be vegetarian.
3. What did God create animals to do?
Most people would agree that God opposes unnecessary cruelty to animals, and would not condone beating cats and dogs to death. Many Christians and Jews are vegetarian or even vegan because they're horrified by how God's animals are treated in industrialized farms. From their perspective, God designed chickens to build nests and raise their chicks; God designed pigs to root in the soil; God designed all animals to breathe fresh air, to play with one another, and so on.
Today, animals used for food are denied everything that God designed them to be and to do when confined and exploited by the meat production industry.
4. But, wait, what about....?
Don't agree? Consider this: Even if religious beliefs allow people to eat factory-farmed meat, they certainly don’t require them to do so. Aside from the environmental, health, and human consequences of eating animals, which are reason enough for faith-based people to adopt a vegan diet, God certainly created animals with needs, desires, and species-specific behaviors, and all these things are denied the animals who are turned into food by the modern farmed-animal industries.
God also created animals with a well-developed capacity for pain, which causes extreme suffering in a factory-farm setting.