Sentient sen·tient (sěn'shənt, -shē-ənt)
adjective
sen·tient (sěn'shənt, -shē-ənt)
1.having the power of perception by the senses; conscious.
2.characterized by sensation and consciousness.
noun
1.a person or thing that is sentient.
2.Archaic. the conscious mind.
Origin:
1595–1605; < L sentient- (s. of sentiēns, prp. of sentīre to feel)

Sentient sen·tient (sěn'shənt, -shē-ənt)
adjective
1.Having sense perception; conscious. Experiencing sensation or feeling sentient
2.1632, "capable of feeling," from L. sentientem (nom. sentiens)
3.Meaning "conscious" (of something) is from 1815.

Therefore:
Animals such as cats, dogs, cows, pigs, chickens, birds, goats, geese, mice, rabbits etc. are sentient beings—capable of awareness, feeling and sensations (including pain) — and humans have an ethical obligation to refrain from behaviour which inflict suffering upon these animals.