off one's feed

Prepositional phrase

of an animal idiomatic of a person

Japanese Meaning

（動物の場合）通常の食欲を示さず、普段の食事をとらない状態 / （人の場合）体調が優れず、特に食欲が低下し、軽い混乱や不調を感じる状態

When a dog is off one's feed, owners should consult a veterinarian promptly.

犬が普段通りに食べていないときは、飼い主はすぐに獣医に相談すべきだ。

Sense（1）

(of an animal) Not eating normally.

"Nothing serious," the veterinarian added. "He was just off his feed a trifle."

Sense（2）

(idiomatic, of a person) Rather unwell, especially with a reduced or altered appetite; somewhat disoriented or disconcerted.