Milk
Cow's Milk
noun
Cow milk is cow's milk, though most people just call cow's milk milk.
ぎゅうにゅう
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
「おはよう。はい、牛乳よ。」「ああ、ありがとう。やっぱりこれだよね。一日の始まりに、美味しい牛乳に勝るものはないね。」
"Good morning. Here’s your milk." "Oh, thanks. That hits the spot. There’s nothing like a great glass of milk to start the day."