Animals often appear in dreams for very personal reasons, and have to do with your own experiences with them.
How you experience an animal in both waking and sleeping is central to its meaning. This includes both how the animal actually behaves in your dream, and your waking stereotypical attitude about the animal. This is important because the two may be juxtaposed.
Consider a dog. Dogs are often considered to be loyal and friendly. However, many people have a deeply rooted fear of dogs. Dogs also have stereotypes that are opposites (for example, man's best friend versus call off the dogs). People with a deeply held fear of dogs may experience a dog dream that validates the fear one night and contradicts it another time.
What the animal is doing is also central to how the dream is interpreted. Are you being chased by animals? Eaten by animals? Talking with animals?
Farm animals are not too unusual in dreams. However, they seem to be less common than they were in more agricultural times. Grazing farm animals generally reflect a sense of being provided for adequately. In early dream history, grazing animals were taken as a sign that prosperity and calm were coming to, or prevalent in, a land.
Killing animals is a more unusual dream theme that divides into two general areas: killing by necessity, and killing arbitrarily. Killing out of necessity could be a hunter-provider archetype dream or a survival dream. These dreams often reflect a sense of responsibility for the other characters in the dream or of a need to prove oneself. Dreams of killing animals arbitrarily may reflect either wish-fulfillment, anger projection, or frustration with a social taboo.
Wish-fulfillment and anger projection have much to do with how you perceive the animal you are killing.
Does this animal have any representation for you among persons in general or do you characterize a specific person as an animal when speaking of them?
The social taboo of arbitrarily wounding or killing animals has become a criterion for evaluating antisocial behavior in people. Consequently, it is not surprising that in dreams this would be a sign of taboo frustration. Again, what the animal represents may be of significance to you.
Starving animals hold significance in agricultural societies and Native American spirituality. These animals often reflect a concern or foreboding about the adequacy of needs being met the future. In the past, starving animals were a reflection or anticipation of famine periods. Starving animals may also be metaphors for relationship transactions in which you participate.
Common animals' stereotypical perceptions that may appear in dreams as metaphors for yourself or others (listed as good-bad): Cat: quiet, independent-aloof, disengaged
Cow: provider, gentle-easily intimidated
Dog: loyal, friendly-consumptive, aggressive
Horse: hardworking, useful-strong-willed, independent
Mouse: quiet; diminutive-unable to assert power
Ox: hardworking-dumb
Pig: clean, smart-gluttonous, dirty
Rabbit: fast, gentle, fertile-timid
See bear, birds, cats, dogs, elephant, fish, fox, oxen, rats, wolf